65 KiB
stage | group | info |
---|---|---|
Systems | Geo | To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/product/ux/technical-writing/#assignments |
Troubleshooting Geo (PREMIUM SELF)
Setting up Geo requires careful attention to details, and sometimes it's easy to miss a step.
Here is a list of steps you should take to attempt to fix problem:
- Perform basic troubleshooting.
- Fix any PostgreSQL database replication errors.
- Fix any common errors.
- Fix any non-PostgreSQL replication failures.
Basic troubleshooting
Before attempting more advanced troubleshooting:
Check the health of the secondary site
On the primary site:
- On the top bar, select Main menu > Admin.
- On the left sidebar, select Geo > Sites.
We perform the following health checks on each secondary site to help identify if something is wrong:
- Is the site running?
- Is the secondary site's database configured for streaming replication?
- Is the secondary site's tracking database configured?
- Is the secondary site's tracking database connected?
- Is the secondary site's tracking database up-to-date?
For information about how to resolve common error messages reported from the user interface, see Fixing Common Errors.
If the user interface is not working, or you are unable to sign in, you can run the Geo health check manually to get this information and a few more details.
Health check Rake task
This Rake task can be run on a Rails node in the primary or secondary Geo sites:
sudo gitlab-rake gitlab:geo:check
Example output:
Checking Geo ...
GitLab Geo is available ... yes
GitLab Geo is enabled ... yes
This machine's Geo node name matches a database record ... yes, found a secondary node named "Shanghai"
GitLab Geo secondary database is correctly configured ... yes
Database replication enabled? ... yes
Database replication working? ... yes
GitLab Geo HTTP(S) connectivity ...
* Can connect to the primary node ... yes
HTTP/HTTPS repository cloning is enabled ... yes
Machine clock is synchronized ... yes
Git user has default SSH configuration? ... yes
OpenSSH configured to use AuthorizedKeysCommand ... yes
GitLab configured to disable writing to authorized_keys file ... yes
GitLab configured to store new projects in hashed storage? ... yes
All projects are in hashed storage? ... yes
Checking Geo ... Finished
Sync status Rake task
Current sync information can be found manually by running this Rake task on any node running Rails (Puma, Sidekiq, or Geo Log Cursor) on the Geo secondary site:
sudo gitlab-rake geo:status
The output includes:
- a count of "failed" items if any failures occurred
- the percentage of "succeeded" items, relative to the "total"
Example:
http://secondary.example.com/
-----------------------------------------------------
GitLab Version: 14.9.2-ee
Geo Role: Secondary
Health Status: Healthy
Repositories: succeeded 12345 / total 12345 (100%)
Verified Repositories: succeeded 12345 / total 12345 (100%)
Wikis: succeeded 6789 / total 6789 (100%)
Verified Wikis: succeeded 6789 / total 6789 (100%)
Attachments: succeeded 4 / total 4 (100%)
CI job artifacts: succeeded 0 / total 0 (0%)
Design repositories: succeeded 1 / total 1 (100%)
LFS Objects: failed 1 / succeeded 2 / total 3 (67%)
Merge Request Diffs: succeeded 0 / total 0 (0%)
Package Files: failed 1 / succeeded 2 / total 3 (67%)
Terraform State Versions: failed 1 / succeeded 2 / total 3 (67%)
Snippet Repositories: failed 1 / succeeded 2 / total 3 (67%)
Group Wiki Repositories: succeeded 4 / total 4 (100%)
Pipeline Artifacts: failed 3 / succeeded 0 / total 3 (0%)
Pages Deployments: succeeded 0 / total 0 (0%)
Repositories Checked: failed 5 / succeeded 0 / total 5 (0%)
Package Files Verified: succeeded 0 / total 10 (0%)
Terraform State Versions Verified: succeeded 0 / total 10 (0%)
Snippet Repositories Verified: succeeded 99 / total 100 (99%)
Pipeline Artifacts Verified: succeeded 0 / total 10 (0%)
Sync Settings: Full
Database replication lag: 0 seconds
Last event ID seen from primary: 12345 (about 2 minutes ago)
Last event ID processed by cursor: 12345 (about 2 minutes ago)
Last status report was: 1 minute ago
To find more details about failed items, check
the gitlab-rails/geo.log
file
If you notice replication or verification failures, you can try to resolve them.
Check if PostgreSQL replication is working
To check if PostgreSQL replication is working, check if:
Are sites pointing to the correct database node?
You should make sure your primary Geo site points to the database node that has write permissions.
Any secondary sites should point only to read-only database nodes.
Can Geo detect the current site correctly?
Geo finds the current Puma or Sidekiq node's Geo site name in
/etc/gitlab/gitlab.rb
with the following logic:
- Get the "Geo node name" (there is
an issue to rename the settings to "Geo site name"):
- Omnibus GitLab: Get the
gitlab_rails['geo_node_name']
setting. - GitLab Helm Charts: Get the
global.geo.nodeName
setting (see Charts with GitLab Geo).
- Omnibus GitLab: Get the
- If that is not defined, then get the
external_url
setting.
This name is used to look up the Geo site with the same Name in the Geo Sites dashboard.
To check if the current machine has a site name that matches a site in the database, run the check task:
sudo gitlab-rake gitlab:geo:check
It displays the current machine's site name and whether the matching database record is a primary or secondary site.
This machine's Geo node name matches a database record ... yes, found a secondary node named "Shanghai"
This machine's Geo node name matches a database record ... no
Try fixing it:
You could add or update a Geo node database record, setting the name to "https://example.com/".
Or you could set this machine's Geo node name to match the name of an existing database record: "London", "Shanghai"
For more information see:
doc/administration/geo/replication/troubleshooting.md#can-geo-detect-the-current-node-correctly
Learn more about recommended site names in the description of the Name field in Geo Admin Area Common Settings.
Reverify all uploads (or any SSF data type which is verified)
- SSH into a GitLab Rails node in the primary Geo site.
- Open Rails console.
- Mark all uploads as "pending verification":
WARNING: Commands that change data can cause damage if not run correctly or under the right conditions. Always run commands in a test environment first and have a backup instance ready to restore.
Upload.verification_state_table_class.each_batch do |relation|
relation.update_all(verification_state: 0)
end
- This will cause the primary to start checksumming all Uploads.
- When a primary successfully checksums a record, then all secondaries rechecksum as well, and they compare the values.
A similar thing can be done for all Models handled by the Geo Self-Service Framework which have implemented verification:
LfsObject
MergeRequestDiff
Packages::PackageFile
Terraform::StateVersion
SnippetRepository
Ci::PipelineArtifact
PagesDeployment
Upload
Ci::JobArtifact
Ci::SecureFile
NOTE:
GroupWikiRepository
is not in the previous list since verification is not implemented.
There is an issue to implement this functionality in the Admin Area UI.
Message: WARNING: oldest xmin is far in the past
and pg_wal
size growing
If a replication slot is inactive,
the pg_wal
logs corresponding to the slot are reserved forever
(or until the slot is active again). This causes continuous disk usage growth
and the following messages appear repeatedly in the
PostgreSQL logs:
WARNING: oldest xmin is far in the past
HINT: Close open transactions soon to avoid wraparound problems.
You might also need to commit or roll back old prepared transactions, or drop stale replication slots.
To fix this:
-
Run
SELECT * FROM pg_replication_slots;
. Note theslot_name
that reportsactive
asf
(false).
Fixing errors found when running the Geo check Rake task
When running this Rake task, you may see error messages if the nodes are not properly configured:
sudo gitlab-rake gitlab:geo:check
-
Rails did not provide a password when connecting to the database.
Checking Geo ... GitLab Geo is available ... Exception: fe_sendauth: no password supplied GitLab Geo is enabled ... Exception: fe_sendauth: no password supplied ... Checking Geo ... Finished
Ensure you have the
gitlab_rails['db_password']
set to the plain-text password used when creating the hash forpostgresql['sql_user_password']
. -
Rails is unable to connect to the database.
Checking Geo ... GitLab Geo is available ... Exception: FATAL: no pg_hba.conf entry for host "1.1.1.1", user "gitlab", database "gitlabhq_production", SSL on FATAL: no pg_hba.conf entry for host "1.1.1.1", user "gitlab", database "gitlabhq_production", SSL off GitLab Geo is enabled ... Exception: FATAL: no pg_hba.conf entry for host "1.1.1.1", user "gitlab", database "gitlabhq_production", SSL on FATAL: no pg_hba.conf entry for host "1.1.1.1", user "gitlab", database "gitlabhq_production", SSL off ... Checking Geo ... Finished
Ensure you have the IP address of the rails node included in
postgresql['md5_auth_cidr_addresses']
. Also, ensure you have included the subnet mask on the IP address:postgresql['md5_auth_cidr_addresses'] = ['1.1.1.1/32']
. -
Rails has supplied the incorrect password.
Checking Geo ... GitLab Geo is available ... Exception: FATAL: password authentication failed for user "gitlab" FATAL: password authentication failed for user "gitlab" GitLab Geo is enabled ... Exception: FATAL: password authentication failed for user "gitlab" FATAL: password authentication failed for user "gitlab" ... Checking Geo ... Finished
Verify the correct password is set for
gitlab_rails['db_password']
that was used when creating the hash inpostgresql['sql_user_password']
by runninggitlab-ctl pg-password-md5 gitlab
and entering the password. -
Check returns
not a secondary node
.Checking Geo ... GitLab Geo is available ... yes GitLab Geo is enabled ... yes GitLab Geo secondary database is correctly configured ... not a secondary node Database replication enabled? ... not a secondary node ... Checking Geo ... Finished
Ensure you have added the secondary site in the Main menu > Admin > Geo > Sites on the web interface for the primary site. Also ensure you entered the
gitlab_rails['geo_node_name']
when adding the secondary site in the Admin Area of the primary site. In GitLab 12.3 and earlier, edit the secondary site in the Admin Area of the primary site and ensure that there is a trailing/
in theName
field. -
Check returns
Exception: PG::UndefinedTable: ERROR: relation "geo_nodes" does not exist
.Checking Geo ... GitLab Geo is available ... no Try fixing it: Add a new license that includes the GitLab Geo feature For more information see: https://about.gitlab.com/features/gitlab-geo/ GitLab Geo is enabled ... Exception: PG::UndefinedTable: ERROR: relation "geo_nodes" does not exist LINE 8: WHERE a.attrelid = '"geo_nodes"'::regclass ^ : SELECT a.attname, format_type(a.atttypid, a.atttypmod), pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod, c.collname, col_description(a.attrelid, a.attnum) AS comment FROM pg_attribute a LEFT JOIN pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum LEFT JOIN pg_type t ON a.atttypid = t.oid LEFT JOIN pg_collation c ON a.attcollation = c.oid AND a.attcollation <> t.typcollation WHERE a.attrelid = '"geo_nodes"'::regclass AND a.attnum > 0 AND NOT a.attisdropped ORDER BY a.attnum ... Checking Geo ... Finished
When performing a PostgreSQL major version (9 > 10) update this is expected. Follow the initiate-the-replication-process.
Message: Machine clock is synchronized ... Exception
The Rake task attempts to verify that the server clock is synchronized with NTP. Synchronized clocks are required for Geo to function correctly. As an example, for security, when the server time on the primary site and secondary site differ by about a minute or more, requests between Geo sites will fail. If this check task fails to complete due to a reason other than mismatching times, it does not necessarily mean that Geo will not work.
The Ruby gem which performs the check is hard coded with pool.ntp.org
as its reference time source.
-
Exception message
Machine clock is synchronized ... Exception: Timeout::Error
This issue occurs when your server cannot access the host
pool.ntp.org
. -
Exception message
Machine clock is synchronized ... Exception: No route to host - recvfrom(2)
This issue occurs when the hostname
pool.ntp.org
resolves to a server which does not provide a time service.
There is an issue open for this dependency on pool.ntp.org
.
To workaround this, do one of the following:
- Add entries in
/etc/hosts
forpool.ntp.org
to direct the request to valid local time servers. This fixes the long timeout and the timeout error. - Direct the check to any valid IP address. This resolves the timeout issue, but the check will fail
with the
No route to host
error, as noted above.
Cloud native GitLab deployments generate an error because containers in Kubernetes do not have access to the host clock:
Machine clock is synchronized ... Exception: getaddrinfo: Servname not supported for ai_socktype
Fixing PostgreSQL database replication errors
The following sections outline troubleshooting steps for fixing replication
error messages (indicated by Database replication working? ... no
in the
geo:check
output.
Message: ERROR: replication slots can only be used if max_replication_slots > 0
?
This means that the max_replication_slots
PostgreSQL variable needs to
be set on the primary database. This setting defaults to 1. You may need to
increase this value if you have more secondary sites.
Be sure to restart PostgreSQL for this to take effect. See the PostgreSQL replication setup guide for more details.
Message: FATAL: could not start WAL streaming: ERROR: replication slot "geo_secondary_my_domain_com" does not exist
?
This occurs when PostgreSQL does not have a replication slot for the secondary site by that name.
You may want to rerun the replication process on the secondary site .
Message: "Command exceeded allowed execution time" when setting up replication?
This may happen while initiating the replication process on the secondary site, and indicates your initial dataset is too large to be replicated in the default timeout (30 minutes).
Re-run gitlab-ctl replicate-geo-database
, but include a larger value for
--backup-timeout
:
sudo gitlab-ctl \
replicate-geo-database \
--host=<primary_node_hostname> \
--slot-name=<secondary_slot_name> \
--backup-timeout=21600
This gives the initial replication up to six hours to complete, rather than the default 30 minutes. Adjust as required for your installation.
Message: "PANIC: could not write to file pg_xlog/xlogtemp.123
: No space left on device"
Determine if you have any unused replication slots in the primary database. This can cause large amounts of
log data to build up in pg_xlog
. Removing the unused slots can reduce the amount of space used in the pg_xlog
.
-
Start a PostgreSQL console session:
sudo gitlab-psql
NOTE: Using
gitlab-rails dbconsole
does not work, because managing replication slots requires superuser permissions. -
View your replication slots:
SELECT * FROM pg_replication_slots;
Slots where active
is f
are not active.
-
When this slot should be active, because you have a secondary site configured using that slot, sign in on the web interface for the secondary site and check the PostgreSQL logs to view why the replication is not running.
-
If you are no longer using the slot (for example, you no longer have Geo enabled), you can remove it with in the PostgreSQL console session:
SELECT pg_drop_replication_slot('<name_of_extra_slot>');
Message: "ERROR: canceling statement due to conflict with recovery"
This error message occurs infrequently under normal usage, and the system is resilient enough to recover.
However, under certain conditions, some database queries on secondaries may run excessively long, which increases the frequency of this error message. This can lead to a situation where some queries never complete due to being canceled on every replication.
These long-running queries are
planned to be removed in the future,
but as a workaround, we recommend enabling
hot_standby_feedback
.
This increases the likelihood of bloat on the primary site as it prevents
VACUUM
from removing recently-dead rows. However, it has been used
successfully in production on GitLab.com.
To enable hot_standby_feedback
, add the following to /etc/gitlab/gitlab.rb
on the secondary site:
postgresql['hot_standby_feedback'] = 'on'
Then reconfigure GitLab:
sudo gitlab-ctl reconfigure
To help us resolve this problem, consider commenting on the issue.
Message: FATAL: could not connect to the primary server: server certificate for "PostgreSQL" does not match host name
This happens because the PostgreSQL certificate that the Omnibus GitLab package automatically creates contains
the Common Name PostgreSQL
, but the replication is connecting to a different host and GitLab attempts to use
the verify-full
SSL mode by default.
To fix this issue, you can either:
- Use the
--sslmode=verify-ca
argument with thereplicate-geo-database
command. - For an already replicated database, change
sslmode=verify-full
tosslmode=verify-ca
in/var/opt/gitlab/postgresql/data/gitlab-geo.conf
and rungitlab-ctl restart postgresql
. - Configure SSL for PostgreSQL with a custom certificate (including the host name that's used to connect to the database in the CN or SAN) instead of using the automatically generated certificate.
Message: LOG: invalid CIDR mask in address
This happens on wrongly-formatted addresses in postgresql['md5_auth_cidr_addresses']
.
2020-03-20_23:59:57.60499 LOG: invalid CIDR mask in address "***"
2020-03-20_23:59:57.60501 CONTEXT: line 74 of configuration file "/var/opt/gitlab/postgresql/data/pg_hba.conf"
To fix this, update the IP addresses in /etc/gitlab/gitlab.rb
under postgresql['md5_auth_cidr_addresses']
to respect the CIDR format (that is, 1.2.3.4/32
).
Message: LOG: invalid IP mask "md5": Name or service not known
This happens when you have added IP addresses without a subnet mask in postgresql['md5_auth_cidr_addresses']
.
2020-03-21_00:23:01.97353 LOG: invalid IP mask "md5": Name or service not known
2020-03-21_00:23:01.97354 CONTEXT: line 75 of configuration file "/var/opt/gitlab/postgresql/data/pg_hba.conf"
To fix this, add the subnet mask in /etc/gitlab/gitlab.rb
under postgresql['md5_auth_cidr_addresses']
to respect the CIDR format (that is, 1.2.3.4/32
).
Message: Found data in the gitlabhq_production database!
when running gitlab-ctl replicate-geo-database
This happens if data is detected in the projects
table. When one or more projects are detected, the operation
is aborted to prevent accidental data loss. To bypass this message, pass the --force
option to the command.
In GitLab 13.4, a seed project is added when GitLab is first installed. This makes it necessary to pass --force
even
on a new Geo secondary site. There is an issue to account for seed projects
when checking the database.
Message: Synchronization failed - Error syncing repository
WARNING: If large repositories are affected by this problem, their resync may take a long time and cause significant load on your Geo sites, storage and network systems.
If you see the error message Synchronization failed - Error syncing repository
along with fatal: fsck error in packed object
, this indicates
a consistency check error when syncing the repository.
One example of a consistency error is: error: object f4a87a3be694fbbd6e50a668a31a8513caeaafe3: hasDotgit: contains '.git
.
Removing the malformed objects causing consistency errors require rewriting the repository history, which is not always an option. However, it's possible to override the consistency checks instead. To do that, follow the instructions in the Gitaly docs.
You can also get the error message Synchronization failed - Error syncing repository
along with the following log messages, this indicates that the expected geo
remote is not present in the .git/config
file
of a repository on the secondary Geo site's file system:
{
"created": "@1603481145.084348757",
"description": "Error received from peer unix:/var/opt/gitlab/gitaly/gitaly.socket",
…
"grpc_message": "exit status 128",
"grpc_status": 13
}
{ …
"grpc.request.fullMethod": "/gitaly.RemoteService/FindRemoteRootRef",
"grpc.request.glProjectPath": "<namespace>/<project>",
…
"level": "error",
"msg": "fatal: 'geo' does not appear to be a git repository
fatal: Could not read from remote repository. …",
}
To solve this:
-
Sign in on the web interface for the secondary Geo site.
-
Back up the
.git
folder. -
Optional. Spot-check a few of those IDs whether they indeed correspond to a project with known Geo replication failures. Use
fatal: 'geo'
as thegrep
term and the following API call:curl --request GET --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/projects/<first_failed_geo_sync_ID>"
-
Enter the Rails console and run:
failed_geo_syncs = Geo::ProjectRegistry.failed.pluck(:id) failed_geo_syncs.each do |fgs| puts Geo::ProjectRegistry.failed.find(fgs).project_id end
-
Run the following commands to reset each project's Geo-related attributes and execute a new sync:
failed_geo_syncs.each do |fgs| registry = Geo::ProjectRegistry.failed.find(fgs) registry.update(resync_repository: true, force_to_redownload_repository: false, repository_retry_count: 0) Geo::RepositorySyncService.new(registry.project).execute end
Very large repositories never successfully synchronize on the secondary site
GitLab places a timeout on all repository clones, including project imports
and Geo synchronization operations. If a fresh git clone
of a repository
on the primary takes more than the default three hours, you may be affected by this.
To increase the timeout:
-
On the Sidekiq nodes on your secondary site, add the following line to
/etc/gitlab/gitlab.rb
:gitlab_rails['gitlab_shell_git_timeout'] = 14400
-
Reconfigure GitLab:
sudo gitlab-ctl reconfigure
This increases the timeout to four hours (14400 seconds). Choose a time long enough to accommodate a full clone of your largest repositories.
New LFS objects are never replicated
If new LFS objects are never replicated to secondary Geo sites, check the version of GitLab you are running. GitLab versions 11.11.x or 12.0.x are affected by a bug that results in new LFS objects not being replicated to Geo secondary sites.
To resolve the issue, upgrade to GitLab 12.1 or later.
Failures during backfill
During a backfill, failures are scheduled to be retried at the end of the backfill queue, therefore these failures only clear up after the backfill completes.
Resetting Geo secondary site replication
If you get a secondary site in a broken state and want to reset the replication state, to start again from scratch, there are a few steps that can help you:
-
Stop Sidekiq and the Geo LogCursor.
It's possible to make Sidekiq stop gracefully, but making it stop getting new jobs and wait until the current jobs to finish processing.
You need to send a SIGTSTP kill signal for the first phase and them a SIGTERM when all jobs have finished. Otherwise just use the
gitlab-ctl stop
commands.gitlab-ctl status sidekiq # run: sidekiq: (pid 10180) <- this is the PID you will use kill -TSTP 10180 # change to the correct PID gitlab-ctl stop sidekiq gitlab-ctl stop geo-logcursor
You can watch the Sidekiq logs to know when Sidekiq jobs processing has finished:
gitlab-ctl tail sidekiq
-
Rename repository storage folders and create new ones. If you are not concerned about possible orphaned directories and files, you can skip this step.
mv /var/opt/gitlab/git-data/repositories /var/opt/gitlab/git-data/repositories.old mkdir -p /var/opt/gitlab/git-data/repositories chown git:git /var/opt/gitlab/git-data/repositories
NOTE: You may want to remove the
/var/opt/gitlab/git-data/repositories.old
in the future as soon as you confirmed that you don't need it anymore, to save disk space. -
Optional. Rename other data folders and create new ones.
WARNING: You may still have files on the secondary site that have been removed from the primary site, but this removal has not been reflected. If you skip this step, these files are not removed from the Geo secondary site.
Any uploaded content (like file attachments, avatars, or LFS objects) is stored in a subfolder in one of these paths:
/var/opt/gitlab/gitlab-rails/shared
/var/opt/gitlab/gitlab-rails/uploads
To rename all of them:
gitlab-ctl stop mv /var/opt/gitlab/gitlab-rails/shared /var/opt/gitlab/gitlab-rails/shared.old mkdir -p /var/opt/gitlab/gitlab-rails/shared mv /var/opt/gitlab/gitlab-rails/uploads /var/opt/gitlab/gitlab-rails/uploads.old mkdir -p /var/opt/gitlab/gitlab-rails/uploads gitlab-ctl start postgresql gitlab-ctl start geo-postgresql
Reconfigure to recreate the folders and make sure permissions and ownership are correct:
gitlab-ctl reconfigure
-
Reset the Tracking Database.
WARNING: If you skipped the optional step 3, be sure both
geo-postgresql
andpostgresql
services are running.gitlab-rake db:drop:geo DISABLE_DATABASE_ENVIRONMENT_CHECK=1 # on a secondary app node gitlab-ctl reconfigure # on the tracking database node gitlab-rake db:migrate:geo # on a secondary app node
-
Restart previously stopped services.
gitlab-ctl start
Design repository failures on mirrored projects and project imports
On the top bar, under Main menu > Admin > Geo > Sites,
if the Design repositories progress bar shows
Synced
and Failed
greater than 100%, and negative Queued
, the instance
is likely affected by
a bug in GitLab 13.2 and 13.3.
It was fixed in GitLab 13.4 and later.
To determine the actual replication status of design repositories in a Rails console:
secondary = Gitlab::Geo.current_node
counts = {}
secondary.designs.select("projects.id").find_each do |p|
registry = Geo::DesignRegistry.find_by(project_id: p.id)
state = registry ? "#{registry.state}" : "registry does not exist yet"
# puts "Design ID##{p.id}: #{state}" # uncomment this for granular information
counts[state] ||= 0
counts[state] += 1
end
puts "\nCounts:", counts
Example output:
Design ID#5: started
Design ID#6: synced
Design ID#7: failed
Design ID#8: pending
Design ID#9: synced
Counts:
{"started"=>1, "synced"=>2, "failed"=>1, "pending"=>1}
Example output if there are actually zero design repository replication failures:
Design ID#5: synced
Design ID#6: synced
Design ID#7: synced
Counts:
{"synced"=>3}
If you are promoting a Geo secondary site running on a single node
gitlab-ctl promotion-preflight-checks
fails due to the existence of
failed
rows in the geo_design_registry
table. Use the
previous snippet to
determine the actual replication status of Design repositories.
gitlab-ctl promote-to-primary-node
fails since it runs preflight checks.
If the previous snippet
shows that all designs are synced, you can use the
--skip-preflight-checks
option or the --force
option to move forward with
promotion.
If you are promoting a Geo secondary site running on multiple servers
gitlab-ctl promotion-preflight-checks
fails due to the existence of
failed
rows in the geo_design_registry
table. Use the
previous snippet to
determine the actual replication status of Design repositories.
Sync failure message: "Verification failed with: Error during verification: File is not checksummable"
Missing files on the Geo primary site
In GitLab 14.5 and earlier, certain data types which were missing on the Geo primary site were marked as "synced" on Geo secondary sites. This was because from the perspective of Geo secondary sites, the state matched the primary site and nothing more could be done on secondary sites.
Secondaries would regularly try to sync these files again by using the "verification" feature:
- Verification fails since the file doesn't exist.
- The file is marked "sync failed".
- Sync is retried.
- The file is marked "sync succeeded".
- The file is marked "needs verification".
- Repeat until the file is available again on the primary site.
This can be confusing to troubleshoot, since the registry entries are moved through a logical loop by various background jobs. Also, last_sync_failure
and verification_failure
are empty after "sync succeeded" but before verification is retried.
If you see sync failures repeatedly and alternately increase, while successes decrease and vice versa, this is likely to be caused by missing files on the primary site. You can confirm this by searching geo.log
on secondary sites for File is not checksummable
affecting the same files over and over.
After confirming this is the problem, the files on the primary site need to be fixed. Some possible causes:
- An NFS share became unmounted.
- A disk died or became corrupted.
- Someone unintentionally deleted a file or directory.
- Bugs in GitLab application:
- A file was moved when it shouldn't have been moved.
- A file wasn't moved when it should have been moved.
- A wrong path was generated in the code.
- A non-atomic backup was restored.
- Services or servers or network infrastructure was interrupted/restarted during use.
The appropriate action sometimes depends on the cause. For example, you can remount an NFS share. Often, a root cause may not be apparent or not useful to discover. If you have regular backups, it may be expedient to look through them and pull files from there.
In some cases, a file may be determined to be of low value, and so it may be worth deleting the record.
Geo itself is an excellent mitigation for files missing on the primary. If a file disappears on the primary but it was already synced to the secondary, you can grab the secondary's file. In cases like this, the File is not checksummable
error message does not occur on Geo secondary sites, and only the primary logs this error message.
This problem is more likely to show up in Geo secondary sites which were set up long after the original GitLab site. In this case, Geo is only surfacing an existing problem.
This behavior affects only the following data types through GitLab 14.6:
Data type | From version |
---|---|
Package Registry | 13.10 |
CI Pipeline Artifacts | 13.11 |
Terraform State Versions | 13.12 |
Infrastructure Registry | 14.0 |
External MR diffs | 14.6 |
LFS Objects | 14.6 |
Pages Deployments | 14.6 |
Uploads | 14.6 |
CI Job Artifacts | 14.6 |
Since GitLab 14.7, files that are missing on the primary site are now treated as sync failures
to make Geo visibly surface data loss risks. The sync/verification loop is
therefore short-circuited. last_sync_failure
is now set to The file is missing on the Geo primary site
.
Failed syncs with GitLab-managed object storage replication
There is an issue in GitLab 14.2 through 14.7 that affects Geo when the GitLab-managed object storage replication is used, causing blob object types to fail synchronization.
Since GitLab 14.2, verification failures result in synchronization failures and cause a re-synchronization of these objects.
As verification is not implemented for files stored in object storage (see issue 13845 for more details), this results in a loop that consistently fails for all objects stored in object storage.
You can work around this by marking the objects as synced and succeeded verification, however be aware that can also mark objects that may be missing from the primary.
To do that, enter the Rails console and run:
Gitlab::Geo.verification_enabled_replicator_classes.each do |klass|
updated = klass.registry_class.failed.where(last_sync_failure: "Verification failed with: Error during verification: File is not checksummable").update_all(verification_checksum: '0000000000000000000000000000000000000000', verification_state: 2, verification_failure: nil, verification_retry_at: nil, state: 2, last_sync_failure: nil, retry_at: nil, verification_retry_count: 0, retry_count: 0)
pp "Updated #{updated} #{klass.replicable_name_plural}"
end
Message: curl 18 transfer closed with outstanding read data remaining & fetch-pack: unexpected disconnect while reading sideband packet
Unstable networking conditions can cause Gitaly to fail when trying to fetch large repository data from the primary site. This is more likely to happen if a repository has to be replicated from scratch between sites.
Geo retries several times, but if the transmission is consistently interrupted
by network hiccups, an alternative method such as rsync
can be used to circumvent git
and
create the initial copy of any repository that fails to be replicated by Geo.
We recommend transferring each failing repository individually and checking for consistency
after each transfer. Follow the single target rsync
instructions
to transfer each affected repository from the primary to the secondary site.
Fixing errors during a failover or when promoting a secondary to a primary site
The following are possible error messages that might be encountered during failover or when promoting a secondary to a primary site with strategies to resolve them.
Message: ActiveRecord::RecordInvalid: Validation failed: Name has already been taken
When promoting a secondary site, you might encounter the following error message:
Running gitlab-rake geo:set_secondary_as_primary...
rake aborted!
ActiveRecord::RecordInvalid: Validation failed: Name has already been taken
/opt/gitlab/embedded/service/gitlab-rails/ee/lib/tasks/geo.rake:236:in `block (3 levels) in <top (required)>'
/opt/gitlab/embedded/service/gitlab-rails/ee/lib/tasks/geo.rake:221:in `block (2 levels) in <top (required)>'
/opt/gitlab/embedded/bin/bundle:23:in `load'
/opt/gitlab/embedded/bin/bundle:23:in `<main>'
Tasks: TOP => geo:set_secondary_as_primary
(See full trace by running task with --trace)
You successfully promoted this node!
If you encounter this message when running gitlab-rake geo:set_secondary_as_primary
or gitlab-ctl promote-to-primary-node
, either:
-
Enter a Rails console and run:
Rails.application.load_tasks; nil Gitlab::Geo.expire_cache! Rake::Task['geo:set_secondary_as_primary'].invoke
-
Upgrade to GitLab 12.6.3 or later if it is safe to do so. For example, if the failover was just a test. A caching-related bug was fixed.
Message: ActiveRecord::RecordInvalid: Validation failed: Enabled Geo primary node cannot be disabled
If you disabled a secondary site, either with the replication pause task (GitLab 13.2) or by using the user interface (GitLab 13.1 and earlier), you must first re-enable the site before you can continue. This is fixed in GitLab 13.4.
This can be fixed in the database.
-
Start a database console:
sudo gitlab-rails dbconsole --database main
In GitLab 14.1 and earlier:
sudo gitlab-rails dbconsole
-
Run the following command, replacing
https://<secondary url>/
with the URL for your secondary node. You can use eitherhttp
orhttps
, but ensure that you end the URL with a slash (/
):UPDATE geo_nodes SET enabled = true WHERE url = 'https://<secondary url>/' AND enabled = false;"
This should update one row.
Message: NoMethodError: undefined method `secondary?' for nil:NilClass
When promoting a secondary site, you might encounter the following error message:
sudo gitlab-rake geo:set_secondary_as_primary
rake aborted!
NoMethodError: undefined method `secondary?' for nil:NilClass
/opt/gitlab/embedded/service/gitlab-rails/ee/lib/tasks/geo.rake:232:in `block (3 levels) in <top (required)>'
/opt/gitlab/embedded/service/gitlab-rails/ee/lib/tasks/geo.rake:221:in `block (2 levels) in <top (required)>'
/opt/gitlab/embedded/bin/bundle:23:in `load'
/opt/gitlab/embedded/bin/bundle:23:in `<main>'
Tasks: TOP => geo:set_secondary_as_primary
(See full trace by running task with --trace)
This command is intended to be executed on a secondary site only, and this error message is displayed if you attempt to run this command on a primary site.
Message: sudo: gitlab-pg-ctl: command not found
When
promoting a secondary site with multiple nodes,
you need to run the gitlab-pg-ctl
command to promote the PostgreSQL
read-replica database.
In GitLab 12.8 and earlier, this command fails with the message:
sudo: gitlab-pg-ctl: command not found
In this case, the workaround is to use the full path to the binary, for example:
sudo /opt/gitlab/embedded/bin/gitlab-pg-ctl promote
GitLab 12.9 and later are unaffected by this error message.
Message: ERROR - Replication is not up-to-date
during gitlab-ctl promotion-preflight-checks
In GitLab 13.7 and earlier, if you have a data type with zero items to sync,
this command reports ERROR - Replication is not up-to-date
even if
replication is actually up-to-date. This bug was fixed in GitLab 13.8 and
later.
Message: ERROR - Replication is not up-to-date
during gitlab-ctl promote-to-primary-node
In GitLab 13.7 and earlier, if you have a data type with zero items to sync,
this command reports ERROR - Replication is not up-to-date
even if
replication is actually up-to-date. If replication and verification output
shows that it is complete, you can add --skip-preflight-checks
to make the command complete promotion. This bug was fixed in GitLab 13.8 and later.
Errors when using --skip-preflight-checks
or --force
In GitLab 13.4 and earlier, you could receive one of the following error messages when using
--skip-preflight-checks
or --force
:
get_ctl_options': invalid option: --skip-preflight-checks (OptionParser::InvalidOption)
get_ctl_options': invalid option: --force (OptionParser::InvalidOption)
This can happen with XFS or file systems that list files in lexical order, because the load order of the Omnibus GitLab command files can be different than expected, and a global function would get redefined. More details can be found in the related issue.
The workaround is to manually run the preflight checks and promote the database, by running the following commands on the Geo secondary site:
sudo gitlab-ctl promotion-preflight-checks
sudo /opt/gitlab/embedded/bin/gitlab-pg-ctl promote
sudo gitlab-ctl reconfigure
sudo gitlab-rake geo:set_secondary_as_primary
Expired artifacts
If you notice for some reason there are more artifacts on the Geo secondary site than on the Geo primary site, you can use the Rake task to cleanup orphan artifact files.
On a Geo secondary site, this command also cleans up all Geo registry record related to the orphan files on disk.
Fixing sign in errors
Message: The redirect URI included is not valid
If you are able to sign in to the web interface for the primary site, but you receive this error message when attempting to sign in to a secondary web interface, you should verify the Geo site's URL matches its external URL.
On the primary site:
- On the top bar, select Main menu > Admin.
- On the left sidebar, select Geo > Sites.
- Find the affected secondary site and select Edit.
- Ensure the URL field matches the value found in
/etc/gitlab/gitlab.rb
inexternal_url "https://gitlab.example.com"
on the Rails nodes of the secondary site.
Fixing common errors
This section documents common error messages reported in the Admin Area on the web interface, and how to fix them.
Geo database configuration file is missing
GitLab cannot find or doesn't have permission to access the database_geo.yml
configuration file.
In an Omnibus GitLab installation, the file should be in /var/opt/gitlab/gitlab-rails/etc
.
If it doesn't exist or inadvertent changes have been made to it, run sudo gitlab-ctl reconfigure
to restore it to its correct state.
If this path is mounted on a remote volume, ensure your volume configuration has the correct permissions.
An existing tracking database cannot be reused
Geo cannot reuse an existing tracking database.
It is safest to use a fresh secondary, or reset the whole secondary by following Resetting Geo secondary site replication.
Geo site has a database that is writable which is an indication it is not configured for replication with the primary site
This error message refers to a problem with the database replica on a secondary site, which Geo expects to have access to. It usually means, either:
- An unsupported replication method was used (for example, logical replication).
- The instructions to set up a Geo database replication were not followed correctly.
- Your database connection details are incorrect, that is you have specified the wrong
user in your
/etc/gitlab/gitlab.rb
file.
Geo secondary sites require two separate PostgreSQL instances:
- A read-only replica of the primary site.
- A regular, writable instance that holds replication metadata. That is, the Geo tracking database.
This error message indicates that the replica database in the secondary site is misconfigured and replication has stopped.
To restore the database and resume replication, you can do one of the following:
If you set up a new secondary from scratch, you must also remove the old site from the Geo cluster.
Geo site does not appear to be replicating the database from the primary site
The most common problems that prevent the database from replicating correctly are:
- Secondary sites cannot reach the primary site. Check credentials and firewall rules.
- SSL certificate problems. Make sure you copied
/etc/gitlab/gitlab-secrets.json
from the primary site. - Database storage disk is full.
- Database replication slot is misconfigured.
- Database is not using a replication slot or another alternative and cannot catch-up because WAL files were purged.
Make sure you follow the Geo database replication instructions for supported configuration.
Geo database version (...) does not match latest migration (...)
If you are using Omnibus GitLab installation, something might have failed during upgrade. You can:
- Run
sudo gitlab-ctl reconfigure
. - Manually trigger the database migration by running:
sudo gitlab-rake db:migrate:geo
as root on the secondary site.
GitLab indicates that more than 100% of repositories were synced
This can be caused by orphaned records in the project registry. You can clear them using a Rake task.
Geo Admin Area returns 404 error for a secondary site
Sometimes sudo gitlab-rake gitlab:geo:check
indicates that Rails nodes of the secondary sites are
healthy, but a 404 Not Found error message for the secondary site is returned in the Geo Admin Area on the web interface for
the primary site.
To resolve this issue:
- Try restarting each Rails, Sidekiq and Gitaly nodes on your secondary site using
sudo gitlab-ctl restart
. - Check
/var/log/gitlab/gitlab-rails/geo.log
on Sidekiq nodes to see if the secondary site is using IPv6 to send its status to the primary site. If it is, add an entry to the primary site using IPv4 in the/etc/hosts
file. Alternatively, you should enable IPv6 on the primary site.
Secondary site returns 502 errors with Geo proxying
When Geo proxying for secondary sites is enabled, and the secondary site user interface returns 502 errors, it is possible that the response header proxied from the primary site is too large.
Check the NGINX logs for errors similar to this example:
2022/01/26 00:02:13 [error] 26641#0: *829148 upstream sent too big header while reading response header from upstream, client: 1.2.3.4, server: geo.staging.gitlab.com, request: "POST /users/sign_in HTTP/2.0", upstream: "http://unix:/var/opt/gitlab/gitlab-workhorse/sockets/socket:/users/sign_in", host: "geo.staging.gitlab.com", referrer: "https://geo.staging.gitlab.com/users/sign_in"
To resolve this issue:
- Set
nginx['proxy_custom_buffer_size'] = '8k'
in/etc/gitlab.rb
on all web nodes on the secondary site. - Reconfigure the secondary using
sudo gitlab-ctl reconfigure
.
If you still get this error, you can further increase the buffer size by repeating the steps above
and changing the 8k
size, for example by doubling it to 16k
.
Geo Admin Area shows 'Unknown' for health status and 'Request failed with status code 401'
If using a load balancer, ensure that the load balancer's URL is set as the external_url
in the
/etc/gitlab/gitlab.rb
of the nodes behind the load balancer.
Geo Admin Area shows 'Unhealthy' after enabling Maintenance Mode
In GitLab 13.9 through GitLab 14.3, when GitLab Maintenance Mode is enabled, the status of Geo secondary sites stops getting updated. After 10 minutes, the status changes to Unhealthy
.
Geo secondary sites continue to replicate and verify data, and the secondary sites should still be usable. You can use the Sync status Rake task to determine the actual status of a secondary site during Maintenance Mode.
This bug was fixed in GitLab 14.4.
Primary site returns 500 error when accessing /admin/geo/replication/projects
Navigating to Admin > Geo > Replication (or /admin/geo/replication/projects
) on a primary Geo site, shows a 500 error, while that same link on the secondary works fine. The primary's production.log
has a similar entry to the following:
Geo::TrackingBase::SecondaryNotConfigured: Geo secondary database is not configured
from ee/app/models/geo/tracking_base.rb:26:in `connection'
[..]
from ee/app/views/admin/geo/projects/_all.html.haml:1
On a Geo primary site this error can be ignored.
This happens because GitLab is attempting to display registries from the Geo tracking database which doesn't exist on the primary site (only the original projects exist on the primary; no replicated projects are present, therefore no tracking database exists).
Secondary site returns 400 error "Request header or cookie too large"
This error can happen when the internal URL of the primary site is incorrect.
For example, when you use a unified URL and the primary site's internal URL is also equal to the external URL. This causes a loop when a secondary site proxies requests to the primary site's internal URL.
To fix this issue, set the primary site's internal URL to a URL that is:
- Unique to the primary site.
- Accessible from all secondary sites.
-
Enter the Rails console on the primary site.
-
Run the following, replacing
https://unique.url.for.primary.site
with your specific internal URL. For example, depending on your network configuration, you could use an IP address, likehttp://1.2.3.4
.GeoNode.where(primary: true).first.update!(internal_url: "https://unique.url.for.primary.site")
Fixing non-PostgreSQL replication failures
If you notice replication failures in Admin > Geo > Sites
or the Sync status Rake task, you can try to resolve the failures with the following general steps:
- Geo will automatically retry failures. If the failures are new and few in number, or if you suspect the root cause is already resolved, then you can wait to see if the failures go away.
- If failures were present for a long time, then many retries have already occurred, and the interval between automatic retries has increased to up to 4 hours depending on the type of failure. If you suspect the root cause is already resolved, you can manually retry replication or verification.
- If the failures persist, use the following sections to try to resolve them.
Manually retry replication or verification
Project Git repositories and Project Wiki Git repositories have the ability in Admin > Geo > Replication
to Resync all
, Reverify all
, or for a single resource, Resync
or Reverify
.
Adding this ability to other data types is proposed in issue 364725.
The following sections describe how to use internal application commands in the Rails console to cause replication or verification immediately.
WARNING: Commands that change data can cause damage if not run correctly or under the right conditions. Always run commands in a test environment first and have a backup instance ready to restore.
Blob types
Ci::JobArtifact
Ci::PipelineArtifact
Ci::SecureFile
LfsObject
MergeRequestDiff
Packages::PackageFile
PagesDeployment
Terraform::StateVersion
Upload
Packages::PackageFile
is used in the following
Rails console
examples, but things generally work the same for the other types.
WARNING: Commands that change data can cause damage if not run correctly or under the right conditions. Always run commands in a test environment first and have a backup instance ready to restore.
The Replicator
The main kinds of classes are Registry, Model, and Replicator. If you have an instance of one of these classes, you can get the others. The Registry and Model mostly manage PostgreSQL DB state. The Replicator knows how to replicate/verify (or it can call a service to do it):
model_record = Packages::PackageFile.last
model_record.replicator.registry.replicator.model_record # just showing that these methods exist
Replicate a package file, synchronously, given an ID
model_record = Packages::PackageFile.find(id)
model_record.replicator.send(:download)
Replicate a package file, synchronously, given a registry ID
registry = Geo::PackageFileRegistry.find(registry_id)
registry.replicator.send(:download)
Verify package files on the secondary manually
This iterates over all package files on the secondary, looking at the
verification_checksum
stored in the database (which came from the primary)
and then calculate this value on the secondary to check if they match. This
does not change anything in the UI:
# Run on secondary
status = {}
Packages::PackageFile.find_each do |package_file|
primary_checksum = package_file.verification_checksum
secondary_checksum = Packages::PackageFile.hexdigest(package_file.file.path)
verification_status = (primary_checksum == secondary_checksum)
status[verification_status.to_s] ||= []
status[verification_status.to_s] << package_file.id
end
# Count how many of each value we get
status.keys.each {|key| puts "#{key} count: #{status[key].count}"}
# See the output in its entirety
status
Reverify all uploads (or any SSF data type which is verified)
-
SSH into a GitLab Rails node in the primary Geo site.
-
Open Rails console.
-
Mark all uploads as "pending verification":
Upload.verification_state_table_class.each_batch do |relation| relation.update_all(verification_state: 0) end
-
This will cause the primary to start checksumming all Uploads.
-
When a primary successfully checksums a record, then all secondaries rechecksum as well, and they compare the values.
For other SSF data types replace Upload
in the command above with the desired model class.
NOTE: There is an issue to implement this functionality in the Admin Area UI.
Repository types, except for project or project wiki repositories
SnippetRepository
GroupWikiRepository
SnippetRepository
is used in the examples below, but things generally work the same for the other Repository types.
Start a Rails console session to enact the following, basic troubleshooting steps.
WARNING: Commands that change data can cause damage if not run correctly or under the right conditions. Always run commands in a test environment first and have a backup instance ready to restore.
The Replicator
The main kinds of classes are Registry, Model, and Replicator. If you have an instance of one of these classes, you can get the others. The Registry and Model mostly manage PostgreSQL DB state. The Replicator knows how to replicate/verify (or it can call a service to do it).
model_record = SnippetRepository.last
model_record.replicator.registry.replicator.model_record # just showing that these methods exist
Replicate a snippet repository, synchronously, given an ID
model_record = SnippetRepository.find(id)
model_record.replicator.send(:sync_repository)
Replicate a snippet repository, synchronously, given a registry ID
registry = Geo::SnippetRepositoryRegistry.find(registry_id)
registry.replicator.send(:sync_repository)
Find failed artifacts
Start a Rails console session to run the following commands:
Geo::JobArtifactRegistry.failed
Find ID
of synced artifacts that are missing on primary
Geo::JobArtifactRegistry.synced.missing_on_primary.pluck(:artifact_id)
Project or project wiki repositories
Find repository verification failures
Start a Rails console session to gather the following, basic troubleshooting information.
WARNING: Commands that change data can cause damage if not run correctly or under the right conditions. Always run commands in a test environment first and have a backup instance ready to restore.
Get the number of verification failed repositories
Geo::ProjectRegistry.verification_failed('repository').count
Find the verification failed repositories
Geo::ProjectRegistry.verification_failed('repository')
Find repositories that failed to sync
Geo::ProjectRegistry.sync_failed('repository')
Resync project and project wiki repositories
Start a Rails console session to enact the following, basic troubleshooting steps.
WARNING: Commands that change data can cause damage if not run correctly or under the right conditions. Always run commands in a test environment first and have a backup instance ready to restore.
Queue up all repositories for resync
When you run this, Sidekiq handles each sync.
Geo::ProjectRegistry.update_all(resync_repository: true, resync_wiki: true)
Sync individual repository now
project = Project.find_by_full_path('<group/project>')
Geo::RepositorySyncService.new(project).execute
Fixing client errors
Authorization errors from LFS HTTP(S) client requests
You may have problems if you're running a version of Git LFS before 2.4.2.
As noted in this authentication issue,
requests redirected from the secondary to the primary site do not properly send the
Authorization header. This may result in either an infinite Authorization <-> Redirect
loop, or Authorization error messages.
Error: Net::ReadTimeout when pushing through SSH on a Geo secondary
When you push large repositories through SSH on a Geo secondary site, you may encounter a timeout. This is because Rails proxies the push to the primary and has a 60 second default timeout, as described in this Geo issue.
Current workarounds are:
- Push through HTTP instead, where Workhorse proxies the request to the primary (or redirects to the primary if Geo proxying is not enabled).
- Push directly to the primary.
Example log (gitlab-shell.log
):
Failed to contact primary https://primary.domain.com/namespace/push_test.git\\nError: Net::ReadTimeout\",\"result\":null}" code=500 method=POST pid=5483 url="http://127.0.0.1:3000/api/v4/geo/proxy_git_push_ssh/push"
Recovering from a partial failover
The partial failover to a secondary Geo site may be the result of a temporary/transient issue. Therefore, first attempt to run the promote command again.
-
SSH into every Sidekiq, PostgresSQL, Gitaly, and Rails node in the secondary site and run one of the following commands:
-
To promote the secondary site to primary:
sudo gitlab-ctl geo promote
-
To promote the secondary site to primary without any further confirmation:
sudo gitlab-ctl geo promote --force
-
-
Verify you can connect to the newly-promoted primary site using the URL used previously for the secondary site.
-
If successful, the secondary site is now promoted to the primary site.
If the above steps are not successful, proceed through the next steps:
-
SSH to every Sidekiq, PostgresSQL, Gitaly and Rails node in the secondary site and perform the following operations:
-
Create a
/etc/gitlab/gitlab-cluster.json
file with the following content:{ "primary": true, "secondary": false }
-
Reconfigure GitLab for the changes to take effect:
sudo gitlab-ctl reconfigure
-
-
Verify you can connect to the newly-promoted primary site using the URL used previously for the secondary site.
-
If successful, the secondary site is now promoted to the primary site.
Check OS locale data compatibility
If different operating systems or different operating system versions are deployed across Geo sites, we recommend that you perform a locale data compatibility check setting up Geo.
Geo uses PostgreSQL and Streaming Replication to replicate data across Geo sites. PostgreSQL uses locale data provided by the operating system’s C library for sorting text. If the locale data in the C library is incompatible across Geo sites, erroneous query results that lead to incorrect behavior on secondary sites. See here for more details.
On all hosts running PostgreSQL, across all Geo sites, run the following shell command:
( echo "1-1"; echo "11" ) | LC_COLLATE=en_US.UTF-8 sort
The output will either look like:
1-1
11
or the reverse order:
11
1-1
If the output is identical on all hosts, then they running compatible versions of locale data.
If the output differs on some hosts, then PostgreSQL replication will not work properly. We advise that you select operating system versions that are compatible.