159 lines
4.5 KiB
Markdown
159 lines
4.5 KiB
Markdown
---
|
|
type: reference
|
|
stage: Enablement
|
|
group: Distribution
|
|
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
|
|
---
|
|
|
|
# Troubleshooting Redis
|
|
|
|
There are a lot of moving parts that needs to be taken care carefully
|
|
in order for the HA setup to work as expected.
|
|
|
|
Before proceeding with the troubleshooting below, check your firewall rules:
|
|
|
|
- Redis machines
|
|
- Accept TCP connection in `6379`
|
|
- Connect to the other Redis machines via TCP in `6379`
|
|
- Sentinel machines
|
|
- Accept TCP connection in `26379`
|
|
- Connect to other Sentinel machines via TCP in `26379`
|
|
- Connect to the Redis machines via TCP in `6379`
|
|
|
|
## Troubleshooting Redis replication
|
|
|
|
You can check if everything is correct by connecting to each server using
|
|
`redis-cli` application, and sending the `info replication` command as below.
|
|
|
|
```shell
|
|
/opt/gitlab/embedded/bin/redis-cli -h <redis-host-or-ip> -a '<redis-password>' info replication
|
|
```
|
|
|
|
When connected to a `Primary` Redis, you will see the number of connected
|
|
`replicas`, and a list of each with connection details:
|
|
|
|
```plaintext
|
|
# Replication
|
|
role:master
|
|
connected_replicas:1
|
|
replica0:ip=10.133.5.21,port=6379,state=online,offset=208037514,lag=1
|
|
master_repl_offset:208037658
|
|
repl_backlog_active:1
|
|
repl_backlog_size:1048576
|
|
repl_backlog_first_byte_offset:206989083
|
|
repl_backlog_histlen:1048576
|
|
```
|
|
|
|
When it's a `replica`, you will see details of the primary connection and if
|
|
its `up` or `down`:
|
|
|
|
```plaintext
|
|
# Replication
|
|
role:replica
|
|
master_host:10.133.1.58
|
|
master_port:6379
|
|
master_link_status:up
|
|
master_last_io_seconds_ago:1
|
|
master_sync_in_progress:0
|
|
replica_repl_offset:208096498
|
|
replica_priority:100
|
|
replica_read_only:1
|
|
connected_replicas:0
|
|
master_repl_offset:0
|
|
repl_backlog_active:0
|
|
repl_backlog_size:1048576
|
|
repl_backlog_first_byte_offset:0
|
|
repl_backlog_histlen:0
|
|
```
|
|
|
|
## Troubleshooting Sentinel
|
|
|
|
If you get an error like: `Redis::CannotConnectError: No sentinels available.`,
|
|
there may be something wrong with your configuration files or it can be related
|
|
to [this issue](https://github.com/redis/redis-rb/issues/531).
|
|
|
|
You must make sure you are defining the same value in `redis['master_name']`
|
|
and `redis['master_pasword']` as you defined for your sentinel node.
|
|
|
|
The way the Redis connector `redis-rb` works with sentinel is a bit
|
|
non-intuitive. We try to hide the complexity in omnibus, but it still requires
|
|
a few extra configurations.
|
|
|
|
---
|
|
|
|
To make sure your configuration is correct:
|
|
|
|
1. SSH into your GitLab application server
|
|
1. Enter the Rails console:
|
|
|
|
```shell
|
|
# For Omnibus installations
|
|
sudo gitlab-rails console
|
|
|
|
# For source installations
|
|
sudo -u git rails console -e production
|
|
```
|
|
|
|
1. Run in the console:
|
|
|
|
```ruby
|
|
redis = Redis.new(Gitlab::Redis::SharedState.params)
|
|
redis.info
|
|
```
|
|
|
|
Keep this screen open and try to simulate a failover below.
|
|
|
|
1. To simulate a failover on primary Redis, SSH into the Redis server and run:
|
|
|
|
```shell
|
|
# port must match your primary redis port, and the sleep time must be a few seconds bigger than defined one
|
|
redis-cli -h localhost -p 6379 DEBUG sleep 20
|
|
```
|
|
|
|
1. Then back in the Rails console from the first step, run:
|
|
|
|
```ruby
|
|
redis.info
|
|
```
|
|
|
|
You should see a different port after a few seconds delay
|
|
(the failover/reconnect time).
|
|
|
|
## Troubleshooting a non-bundled Redis with an installation from source
|
|
|
|
If you get an error in GitLab like `Redis::CannotConnectError: No sentinels available.`,
|
|
there may be something wrong with your configuration files or it can be related
|
|
to [this upstream issue](https://github.com/redis/redis-rb/issues/531).
|
|
|
|
You must make sure that `resque.yml` and `sentinel.conf` are configured correctly,
|
|
otherwise `redis-rb` will not work properly.
|
|
|
|
The `master-group-name` (`gitlab-redis`) defined in (`sentinel.conf`)
|
|
**must** be used as the hostname in GitLab (`resque.yml`):
|
|
|
|
```conf
|
|
# sentinel.conf:
|
|
sentinel monitor gitlab-redis 10.0.0.1 6379 2
|
|
sentinel down-after-milliseconds gitlab-redis 10000
|
|
sentinel config-epoch gitlab-redis 0
|
|
sentinel leader-epoch gitlab-redis 0
|
|
```
|
|
|
|
```yaml
|
|
# resque.yaml
|
|
production:
|
|
url: redis://:myredispassword@gitlab-redis/
|
|
sentinels:
|
|
-
|
|
host: 10.0.0.1
|
|
port: 26379 # point to sentinel, not to redis port
|
|
-
|
|
host: 10.0.0.2
|
|
port: 26379 # point to sentinel, not to redis port
|
|
-
|
|
host: 10.0.0.3
|
|
port: 26379 # point to sentinel, not to redis port
|
|
```
|
|
|
|
When in doubt, read the [Redis Sentinel documentation](https://redis.io/topics/sentinel).
|