344 lines
18 KiB
Markdown
344 lines
18 KiB
Markdown
---
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stage: Enablement
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group: Geo
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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/#assignments
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---
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# Geo **(PREMIUM SELF)**
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Geo is the solution for widely distributed development teams and for providing
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a warm-standby as part of a disaster recovery strategy.
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## Overview
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WARNING:
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Geo undergoes significant changes from release to release. Upgrades are
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supported and [documented](#updating-geo), but you should ensure that you're
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using the right version of the documentation for your installation.
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Fetching large repositories can take a long time for teams located far from a single GitLab instance.
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Geo provides local, read-only sites of your GitLab instances. This can reduce the time it takes
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to clone and fetch large repositories, speeding up development.
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For a video introduction to Geo, see [Introduction to GitLab Geo - GitLab Features](https://www.youtube.com/watch?v=-HDLxSjEh6w).
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To make sure you're using the right version of the documentation, go to [the Geo page on GitLab.com](https://gitlab.com/gitlab-org/gitlab/-/blob/master/doc/administration/geo/index.md) and choose the appropriate release from the **Switch branch/tag** dropdown list. For example, [`v13.7.6-ee`](https://gitlab.com/gitlab-org/gitlab/-/blob/v13.7.6-ee/doc/administration/geo/index.md).
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Geo uses a set of defined terms that are described in the [Geo Glossary](glossary.md).
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Be sure to familiarize yourself with those terms.
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## Use cases
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Implementing Geo provides the following benefits:
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- Reduce from minutes to seconds the time taken for your distributed developers to clone and fetch large repositories and projects.
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- Enable all of your developers to contribute ideas and work in parallel, no matter where they are.
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- Balance the read-only load between your **primary** and **secondary** sites.
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In addition, it:
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- Can be used for cloning and fetching projects, in addition to reading any data available in the GitLab web interface (see [limitations](#limitations)).
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- Overcomes slow connections between distant offices, saving time by improving speed for distributed teams.
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- Helps reducing the loading time for automated tasks, custom integrations, and internal workflows.
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- Can quickly fail over to a **secondary** site in a [disaster recovery](disaster_recovery/index.md) scenario.
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- Allows [planned failover](disaster_recovery/planned_failover.md) to a **secondary** site.
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Geo provides:
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- Read-only **secondary** sites: Maintain one **primary** GitLab site while still enabling read-only **secondary** sites for each of your distributed teams.
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- Authentication system hooks: **Secondary** sites receives all authentication data (like user accounts and logins) from the **primary** instance.
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- An intuitive UI: **Secondary** sites use the same web interface your team has grown accustomed to. In addition, there are visual notifications that block write operations and make it clear that a user is on a **secondary** sites.
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### Gitaly Cluster
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Geo should not be confused with [Gitaly Cluster](../gitaly/praefect.md). For more information about
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the difference between Geo and Gitaly Cluster, see
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[How does Gitaly Cluster compare to Geo?](../gitaly/faq.md#how-does-gitaly-cluster-compare-to-geo).
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## How it works
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Your Geo instance can be used for cloning and fetching projects, in addition to reading any data. This makes working with large repositories over large distances much faster.
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![Geo overview](replication/img/geo_overview.png)
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When Geo is enabled, the:
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- Original instance is known as the **primary** site.
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- Replicated read-only sites are known as **secondary** sites.
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Keep in mind that:
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- **Secondary** sites talk to the **primary** site to:
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- Get user data for logins (API).
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- Replicate repositories, LFS Objects, and Attachments (HTTPS + JWT).
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- The **primary** site doesn't talk to **secondary** sites to notify for changes (API).
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- You can push directly to a **secondary** site (for both HTTP and SSH,
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including Git LFS).
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- There are [limitations](#limitations) when using Geo.
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### Architecture
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The following diagram illustrates the underlying architecture of Geo.
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![Geo architecture](replication/img/geo_architecture.png)
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In this diagram:
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- There is the **primary** site and the details of one **secondary** site.
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- Writes to the database can only be performed on the **primary** site. A **secondary** site receives database
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updates via PostgreSQL streaming replication.
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- If present, the [LDAP server](#ldap) should be configured to replicate for [Disaster Recovery](disaster_recovery/index.md) scenarios.
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- A **secondary** site performs different type of synchronizations against the **primary** site, using a special
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authorization protected by JWT:
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- Repositories are cloned/updated via Git over HTTPS.
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- Attachments, LFS objects, and other files are downloaded via HTTPS using a private API endpoint.
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From the perspective of a user performing Git operations:
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- The **primary** site behaves as a full read-write GitLab instance.
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- **Secondary** sites are read-only but proxy Git push operations to the **primary** site. This makes **secondary** sites appear to support push operations themselves.
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To simplify the diagram, some necessary components are omitted.
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- Git over SSH requires [`gitlab-shell`](https://gitlab.com/gitlab-org/gitlab-shell) and OpenSSH.
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- Git over HTTPS required [`gitlab-workhorse`](https://gitlab.com/gitlab-org/gitlab-workhorse).
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A **secondary** site needs two different PostgreSQL databases:
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- A read-only database instance that streams data from the main GitLab database.
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- [Another database instance](#geo-tracking-database) used internally by the **secondary** site to record what data has been replicated.
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In **secondary** sites, there is an additional daemon: [Geo Log Cursor](#geo-log-cursor).
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## Requirements for running Geo
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The following are required to run Geo:
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- An operating system that supports OpenSSH 6.9 or later (needed for
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[fast lookup of authorized SSH keys in the database](../operations/fast_ssh_key_lookup.md))
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The following operating systems are known to ship with a current version of OpenSSH:
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- [CentOS](https://www.centos.org) 7.4 or later
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- [Ubuntu](https://ubuntu.com) 16.04 or later
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- PostgreSQL 12 with [Streaming Replication](https://wiki.postgresql.org/wiki/Streaming_Replication)
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- PostgreSQL 13 is not supported for Geo, see [epic 3832](https://gitlab.com/groups/gitlab-org/-/epics/3832)
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- Git 2.9 or later
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- Git-lfs 2.4.2 or later on the user side when using LFS
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- All sites must run the same GitLab version.
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Additionally, check the GitLab [minimum requirements](../../install/requirements.md),
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and we recommend you use the latest version of GitLab for a better experience.
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### Firewall rules
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The following table lists basic ports that must be open between the **primary** and **secondary** sites for Geo. To simplify failovers, we recommend opening ports in both directions.
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| Source site | Source port | Destination site | Destination port | Protocol |
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|-------------|-------------|------------------|------------------|-------------|
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| Primary | Any | Secondary | 80 | TCP (HTTP) |
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| Primary | Any | Secondary | 443 | TCP (HTTPS) |
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| Secondary | Any | Primary | 80 | TCP (HTTP) |
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| Secondary | Any | Primary | 443 | TCP (HTTPS) |
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| Secondary | Any | Primary | 5432 | TCP |
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See the full list of ports used by GitLab in [Package defaults](../package_information/defaults.md)
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NOTE:
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[Web terminal](../../ci/environments/index.md#web-terminals-deprecated) support requires your load balancer to correctly handle WebSocket connections.
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When using HTTP or HTTPS proxying, your load balancer must be configured to pass through the `Connection` and `Upgrade` hop-by-hop headers. See the [web terminal](../integration/terminal.md) integration guide for more details.
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NOTE:
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When using HTTPS protocol for port 443, you must add an SSL certificate to the load balancers.
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If you wish to terminate SSL at the GitLab application server instead, use TCP protocol.
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#### Internal URL
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HTTP requests from any Geo secondary site to the primary Geo site use the Internal URL of the primary
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Geo site. If this is not explicitly defined in the primary Geo site settings in the Admin Area, the
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public URL of the primary site is used.
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To update the internal URL of the primary Geo site:
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1. On the top bar, go to **Menu > Admin > Geo > Sites**.
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1. Select **Edit** on the primary site.
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1. Change the **Internal URL**, then select **Save changes**.
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### LDAP
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We recommend that if you use LDAP on your **primary** site, you also set up secondary LDAP servers on each **secondary** site. Otherwise, users are unable to perform Git operations over HTTP(s) on the **secondary** site using HTTP Basic Authentication. However, Git via SSH and personal access tokens still works.
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NOTE:
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It is possible for all **secondary** sites to share an LDAP server, but additional latency can be an issue. Also, consider what LDAP server is available in a [disaster recovery](disaster_recovery/index.md) scenario if a **secondary** site is promoted to be a **primary** site.
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Check for instructions on how to set up replication in your LDAP service. Instructions are different depending on the software or service used. For example, OpenLDAP provides [these instructions](https://www.openldap.org/doc/admin24/replication.html).
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### Geo Tracking Database
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The tracking database instance is used as metadata to control what needs to be updated on the disk of the local instance. For example:
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- Download new assets.
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- Fetch new LFS Objects.
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- Fetch changes from a repository that has recently been updated.
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Because the replicated database instance is read-only, we need this additional database instance for each **secondary** site.
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### Geo Log Cursor
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This daemon:
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- Reads a log of events replicated by the **primary** site to the **secondary** database instance.
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- Updates the Geo Tracking Database instance with changes that must be executed.
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When something is marked to be updated in the tracking database instance, asynchronous jobs running on the **secondary** site execute the required operations and update the state.
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This new architecture allows GitLab to be resilient to connectivity issues between the sites. It doesn't matter how long the **secondary** site is disconnected from the **primary** site as it is able to replay all the events in the correct order and become synchronized with the **primary** site again.
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## Limitations
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WARNING:
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This list of limitations only reflects the latest version of GitLab. If you are using an older version, extra limitations may be in place.
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- Pushing directly to a **secondary** site redirects (for HTTP) or proxies (for SSH) the request to the **primary** site instead of [handling it directly](https://gitlab.com/gitlab-org/gitlab/-/issues/1381), except when using Git over HTTP with credentials embedded in the URI. For example, `https://user:password@secondary.tld`.
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- The **primary** site has to be online for OAuth login to happen. Existing sessions and Git are not affected. Support for the **secondary** site to use an OAuth provider independent from the primary is [being planned](https://gitlab.com/gitlab-org/gitlab/-/issues/208465).
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- The installation takes multiple manual steps that together can take about an hour depending on circumstances. Consider using [the GitLab Environment Toolkit](https://gitlab.com/gitlab-org/gitlab-environment-toolkit) to deploy and operate production GitLab instances based on our [Reference Architectures](../reference_architectures/index.md), including automation of common daily tasks. We are planning to [improve Geo's installation even further](https://gitlab.com/groups/gitlab-org/-/epics/1465).
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- Real-time updates of issues/merge requests (for example, via long polling) doesn't work on the **secondary** site.
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- GitLab Runners cannot register with a **secondary** site. Support for this is [planned for the future](https://gitlab.com/gitlab-org/gitlab/-/issues/3294).
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- [Selective synchronization](replication/configuration.md#selective-synchronization) only limits what repositories and files are replicated. The entire PostgreSQL data is still replicated. Selective synchronization is not built to accommodate compliance / export control use cases.
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- [Pages access control](../../user/project/pages/pages_access_control.md) doesn't work on secondaries. See [GitLab issue #9336](https://gitlab.com/gitlab-org/gitlab/-/issues/9336) for details.
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### Limitations on replication/verification
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There is a complete list of all GitLab [data types](replication/datatypes.md) and [existing support for replication and verification](replication/datatypes.md#limitations-on-replicationverification).
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### View replication data on the primary site
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If you try to view replication data on the primary site, you receive a warning that this may be inconsistent:
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> Viewing projects and designs data from a primary site is not possible when using a unified URL. Visit the secondary site directly.
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The only way to view projects replication data for a particular secondary site is to visit that secondary site directly. For example, `https://<IP of your secondary site>/admin/geo/replication/projects`.
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An [epic exists](https://gitlab.com/groups/gitlab-org/-/epics/4623) to fix this limitation.
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The only way to view designs replication data for a particular secondary site is to visit that secondary site directly. For example, `https://<IP of your secondary site>/admin/geo/replication/designs`.
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An [epic exists](https://gitlab.com/groups/gitlab-org/-/epics/4624) to fix this limitation.
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## Setup instructions
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For setup instructions, see [Setting up Geo](setup/index.md).
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## Post-installation documentation
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After installing GitLab on the **secondary** sites and performing the initial configuration, see the following documentation for post-installation information.
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### Configuring Geo
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For information on configuring Geo, see [Geo configuration](replication/configuration.md).
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### Updating Geo
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For information on how to update your Geo sites to the latest GitLab version, see [Updating the Geo sites](replication/updating_the_geo_sites.md).
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### Pausing and resuming replication
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> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/35913) in GitLab 13.2.
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WARNING:
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In GitLab 13.2 and 13.3, promoting a secondary site to a primary while the
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secondary is paused fails. Do not pause replication before promoting a
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secondary. If the site is paused, be sure to resume before promoting. This
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issue has been fixed in GitLab 13.4 and later.
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WARNING:
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Pausing and resuming of replication is only supported for Geo installations using an
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Omnibus GitLab-managed database. External databases are not supported.
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In some circumstances, like during [upgrades](replication/updating_the_geo_sites.md) or a [planned failover](disaster_recovery/planned_failover.md), it is desirable to pause replication between the primary and secondary.
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Pausing and resuming replication is done via a command line tool from the node in the secondary site where the `postgresql` service is enabled.
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If `postgresql` is on a standalone database node, ensure that `gitlab.rb` on that node contains the configuration line `gitlab_rails['geo_node_name'] = 'node_name'`, where `node_name` is the same as the `geo_name_name` on the application node.
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**To Pause: (from secondary)**
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```shell
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gitlab-ctl geo-replication-pause
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```
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**To Resume: (from secondary)**
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```shell
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gitlab-ctl geo-replication-resume
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```
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### Configuring Geo for multiple nodes
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For information on configuring Geo for multiple nodes, see [Geo for multiple servers](replication/multiple_servers.md).
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### Configuring Geo with Object Storage
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For information on configuring Geo with object storage, see [Geo with Object storage](replication/object_storage.md).
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### Disaster Recovery
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For information on using Geo in disaster recovery situations to mitigate data-loss and restore services, see [Disaster Recovery](disaster_recovery/index.md).
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### Replicating the Container Registry
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For more information on how to replicate the Container Registry, see [Docker Registry for a **secondary** site](replication/docker_registry.md).
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### Geo secondary proxy
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For more information on using Geo proxying on secondary sites, see [Geo proxying for secondary sites](secondary_proxy/index.md).
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### Security Review
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For more information on Geo security, see [Geo security review](replication/security_review.md).
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### Tuning Geo
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For more information on tuning Geo, see [Tuning Geo](replication/tuning.md).
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### Set up a location-aware Git URL
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For an example of how to set up a location-aware Git remote URL with AWS Route53, see [Location-aware Git remote URL with AWS Route53](replication/location_aware_git_url.md).
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### Backfill
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Once a **secondary** site is set up, it starts replicating missing data from
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the **primary** site in a process known as **backfill**. You can monitor the
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synchronization process on each Geo site from the **primary** site's **Geo Nodes**
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dashboard in your browser.
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Failures that happen during a backfill are scheduled to be retried at the end
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of the backfill.
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## Remove Geo site
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For more information on removing a Geo site, see [Removing **secondary** Geo sites](replication/remove_geo_site.md).
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## Disable Geo
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To find out how to disable Geo, see [Disabling Geo](replication/disable_geo.md).
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## Frequently Asked Questions
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For answers to common questions, see the [Geo FAQ](replication/faq.md).
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## Log files
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Geo stores structured log messages in a `geo.log` file. For Omnibus GitLab
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installations, this file is at `/var/log/gitlab/gitlab-rails/geo.log`.
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This file contains information about when Geo attempts to sync repositories and files. Each line in the file contains a separate JSON entry that can be ingested into. For example, Elasticsearch or Splunk.
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For example:
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```json
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{"severity":"INFO","time":"2017-08-06T05:40:16.104Z","message":"Repository update","project_id":1,"source":"repository","resync_repository":true,"resync_wiki":true,"class":"Gitlab::Geo::LogCursor::Daemon","cursor_delay_s":0.038}
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```
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This message shows that Geo detected that a repository update was needed for project `1`.
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## Troubleshooting
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For troubleshooting steps, see [Geo Troubleshooting](replication/troubleshooting.md).
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