Commit 6239d350 authored by James Ramsay's avatar James Ramsay

Documentation: improve detail and structure

parent 6ed40ca0
# Praefect
# Praefect: High Availability
NOTE: **Note:** Praefect is an experimental service, and for testing purposes only at
this time.
NOTE: **Note:** Praefect is an experimental service, and data loss is likely.
Praefect is an optional reverse-proxy for [Gitaly](../index.md) to manage a
cluster of Gitaly nodes for high availability through replication.
If a Gitaly node becomes unavailable, it will be possible to fail over to a
warm Gitaly replica.
cluster of Gitaly nodes for high availability. Initially, high availability
be implemented through asynchronous replication. If a Gitaly node becomes
unavailable, it will be possible to fail over to a warm Gitaly replica.
The first minimal version will support:
- Eventual consistency of the secondary replicas.
- Manual fail over from the primary to the secondary.
- Automatic fail over from the primary to the secondary.
- Reporting of possible data loss if replication queue is non empty.
Follow the [HA Gitaly epic](https://gitlab.com/groups/gitlab-org/-/epics/1489)
for updates and roadmap.
## Omnibus
## Requirements for configuring Gitaly for High Availability
### Architecture
NOTE: **Note:** this reference architecture is not highly available because
Praefect is a single point of failure.
The most common architecture for Praefect is simplified in the diagram below:
The minimal [alpha](https://about.gitlab.com/handbook/product/#alpha-beta-ga)
reference architecture additionally requires:
```mermaid
graph TB
GitLab --> Praefect;
Praefect --- PostgreSQL;
Praefect --> Gitaly1;
Praefect --> Gitaly2;
Praefect --> Gitaly3;
```
- 1 Praefect node
- 1 PostgreSQL server (PostgreSQL 9.6 or newer)
- 3 Gitaly nodes (1 primary, 2 secondary)
![Alpha architecture diagram](img/praefect_architecture_v12_9.png)
See the [design
document](https://gitlab.com/gitlab-org/gitaly/-/blob/master/doc/design_ha.md)
for implementation details.
## Setup Instructions
If you [installed](https://about.gitlab.com/install/) GitLab using the Omnibus
package (highly recommended), follow the steps below:
1. [Preparation](#preparation)
1. [Configuring the Praefect database](#postgresql)
1. [Configuring the Praefect proxy/router](#praefect)
1. [Configuring each Gitaly node](#gitaly) (once for each Gitaly node)
1. [Updating the GitLab server configuration](#gitlab)
Where `GitLab` is the collection of clients that can request Git operations.
The Praefect node has three storage nodes attached. Praefect itself doesn't
store data, but connects to three Gitaly nodes, `Gitaly-1`, `Gitaly-2`, and `Gitaly-3`.
### Preparation
In order to keep track of replication state, Praefect relies on a
PostgreSQL database. This database is a single point of failure so you
should use a highly available PostgreSQL server for this. GitLab
itself needs a HA PostgreSQL server too, so you could optionally co-locate the Praefect
SQL database on the PostgreSQL server you use for the rest of GitLab.
Before beginning, you should already have a working GitLab instance. [Learn how
to install GitLab](https://about.gitlab.com/install/).
Praefect may be enabled on its own node or can be run on the GitLab server.
In the example below we will use a separate server, but the optimal configuration
for Praefect is still being determined.
Provision a PostgreSQL server (PostgreSQL 9.6 or newer). Configuration through
the GitLab Omnibus distribution is not yet supported. Follow this
[issue](https://gitlab.com/gitlab-org/gitaly/issues/2476) for updates.
Praefect will handle all Gitaly RPC requests to its child nodes. However, the child nodes
will still need to communicate with the GitLab server via its internal API for authentication
purposes.
Prepare all your new nodes by [installing
GitLab](https://about.gitlab.com/install/).
### Setup
- 1 Praefect node (minimal storage required)
- 3 Gitaly nodes (high CPU, high memory, fast storage)
In this setup guide we will start by configuring Praefect, then its child
Gitaly nodes, and lastly the GitLab server configuration.
You will need the IP/host address for each node.
1. `POSTGRESQL_SERVER_ADDRESS`: the IP/host address of the PostgreSQL server
1. `PRAEFECT_SERVER_ADDRESS`: the IP/host address of the Praefect server
1. `GITALY_SERVER_ADDRESS`: the IP/host address of each Gitaly node
#### Secrets
We need to manage the following secrets and make them match across hosts:
1. `GITLAB_SHELL_SECRET_TOKEN`: this is used by Git hooks to make
callback HTTP API requests to GitLab when accepting a Git push. This
secret is shared with GitLab Shell for legacy reasons.
1. `PRAEFECT_EXTERNAL_TOKEN`: repositories hosted on your Praefect
cluster can only be accessed by Gitaly clients that carry this
token.
1. `PRAEFECT_INTERNAL_TOKEN`: this token is used for replication
traffic inside your Praefect cluster. This is distinct from
`PRAEFECT_EXTERNAL_TOKEN` because Gitaly clients must not be able to
access internal nodes of the Praefect cluster directly; that could
lead to data loss.
The communication between components is secured with different secrets, which
are described below. Before you begin, generate a unique secret for each, and
make note of it. This will make it easy to replace these placeholder tokens
with secure tokens as you complete the setup process.
1. `GITLAB_SHELL_SECRET_TOKEN`: this is used by Git hooks to make callback HTTP
API requests to GitLab when accepting a Git push. This secret is shared with
GitLab Shell for legacy reasons.
1. `PRAEFECT_EXTERNAL_TOKEN`: repositories hosted on your Praefect cluster can
only be accessed by Gitaly clients that carry this token.
1. `PRAEFECT_INTERNAL_TOKEN`: this token is used for replication traffic inside
your Praefect cluster. This is distinct from `PRAEFECT_EXTERNAL_TOKEN`
because Gitaly clients must not be able to access internal nodes of the
Praefect cluster directly; that could lead to data loss.
1. `PRAEFECT_SQL_PASSWORD`: this password is used by Praefect to connect to
PostgreSQL.
We will note in the instructions below where these secrets are required.
#### Network addresses
### PostgreSQL
1. `POSTGRESQL_SERVER_ADDRESS`: the host name or IP address of your PostgreSQL server
NOTE: **Note:** don't reuse the GitLab application database for the Praefect
database.
#### PostgreSQL
To complete this section you will need:
To set up a Praefect cluster you need a highly available PostgreSQL
server. You need PostgreSQL 9.6 or newer. Praefect needs to have a SQL
user with the right to create databases.
- 1 Praefect node
- 1 PostgreSQL server (PostgreSQL 9.6 or newer)
- An SQL user with permissions to create databases
In the instructions below we assume you have administrative access to
your PostgreSQL server via `psql`. Depending on your environment, you
may also be able to do this via the web interface of your cloud
platform, or via your configuration management system, etc.
During this section, we will configure the PostgreSQL server, from the Praefect
node, using `psql` which is installed by GitLab Omnibus.
Below we assume that you have administrative access as the `postgres`
user. First open a `psql` session as the `postgres` user:
1. SSH into the **Praefect** node and login as root:
```shell
/opt/gitlab/embedded/bin/psql -h POSTGRESQL_SERVER_ADDRESS -U postgres -d template1
```
```shell
sudo -i
```
Once you are connected, run the following command. Replace
`PRAEFECT_SQL_PASSWORD` with the actual (random) password you
generated for the `praefect` SQL user:
1. Connect to the PostgreSQL server with administrative access. This is likely
the `postgres` user. The database `template1` is used because it is created
by default on all PostgreSQL servers.
```sql
CREATE ROLE praefect WITH LOGIN CREATEDB PASSWORD 'PRAEFECT_SQL_PASSWORD';
\q
```
```shell
/opt/gitlab/embedded/bin/psql -U postgres -d template1 -h POSTGRESQL_SERVER_ADDRESS
```
Now connect as the `praefect` user to create the database. This has
the side effect of verifying that you have access:
Create a new user `praefect` which will be used by Praefect. Replace
`PRAEFECT_SQL_PASSWORD` with the strong password you generated in the
preparation step.
```shell
/opt/gitlab/embedded/bin/psql -h POSTGRESQL_SERVER_ADDRESS -U praefect -d template1
```
```sql
CREATE ROLE praefect WITH LOGIN CREATEDB PASSWORD 'PRAEFECT_SQL_PASSWORD';
```
Once you have connected as the `praefect` user, run:
1. Reconnect to the PostgreSQL server, this time as the `praefect` user:
```sql
CREATE DATABASE praefect_production WITH ENCODING=UTF8;
\q
```
```shell
/opt/gitlab/embedded/bin/psql -U praefect -d template1 -h POSTGRESQL_SERVER_ADDRESS
```
Create a new database `praefect_production`. By creating the database while
connected as the `praefect` user, we are confident they have access.
```sql
CREATE DATABASE praefect_production WITH ENCODING=UTF8;
```
The database used by Praefect is now configured.
### Praefect
To complete this section you will need:
- [Configured PostgreSQL server](#postgresql), including:
- IP/host address (`POSTGRESQL_SERVER_ADDRESS`)
- password (`PRAEFECT_SQL_PASSWORD`)
Praefect should be run on a dedicated node. Do not run Praefect on the
application server, or a Gitaly node.
1. SSH into the **Praefect** node and login as root:
```shell
sudo -i
```
1. Disable all other services by editing `/etc/gitlab/gitlab.rb`:
#### Praefect
```ruby
# Disable all other services on the Praefect node
postgresql['enable'] = false
redis['enable'] = false
nginx['enable'] = false
prometheus['enable'] = false
grafana['enable'] = false
unicorn['enable'] = false
sidekiq['enable'] = false
gitlab_workhorse['enable'] = false
gitaly['enable'] = false
On the Praefect node we disable all other services, including Gitaly. We list each
Gitaly node that will be connected to Praefect as members of the `praefect` hash in `praefect['virtual_storages']`.
# Enable only the Praefect service
praefect['enable'] = true
In the example below, the Gitaly nodes are named `gitaly-N`. Note that one
node is designated as primary by setting the primary to `true`.
# Prevent database connections during 'gitlab-ctl reconfigure'
gitlab_rails['rake_cache_clear'] = false
gitlab_rails['auto_migrate'] = false
```
If you are using an uncrypted connection to Postgres, set `praefect['database_sslmode']` to false.
1. Configure **Praefect** to listen on network interfaces by editing
`/etc/gitlab/gitlab.rb`:
If you are using an encrypted connection with a client certificate,
`praefect['database_sslcert']` and `praefect['database_sslkey']` will need to be set.
If you are using a custom CA, also set `praefect['database_sslrootcert']`:
```ruby
# Make Praefect accept connections on all network interfaces.
# Use firewalls to restrict access to this address/port.
praefect['listen_addr'] = '0.0.0.0:2305'
```
```ruby
# /etc/gitlab/gitlab.rb on praefect server
1. Configure a strong `auth_token` for **Praefect** by editing
`/etc/gitlab/gitlab.rb`. This will be needed by clients outside the cluster
(like GitLab Shell) to communicate with the Praefect cluster :
# Avoid running unnecessary services on the Gitaly server
postgresql['enable'] = false
redis['enable'] = false
nginx['enable'] = false
prometheus['enable'] = false
grafana['enable'] = false
unicorn['enable'] = false
sidekiq['enable'] = false
gitlab_workhorse['enable'] = false
gitaly['enable'] = false
```ruby
praefect['auth_token'] = 'PRAEFECT_EXTERNAL_TOKEN'
```
# Prevent database connections during 'gitlab-ctl reconfigure'
gitlab_rails['rake_cache_clear'] = false
gitlab_rails['auto_migrate'] = false
1. Configure **Praefect** to connect to the PostgreSQL database by editing
`/etc/gitlab/gitlab.rb`.
praefect['enable'] = true
You will need to replace `POSTGRESQL_SERVER_ADDRESS` with the IP/host address
of the database, and `PRAEFECT_SQL_PASSWORD` with the strong password set
above.
# Make Praefect accept connections on all network interfaces. You must use
# firewalls to restrict access to this address/port.
praefect['listen_addr'] = '0.0.0.0:2305'
```ruby
praefect['database_host'] = 'POSTGRESQL_SERVER_ADDRESS'
praefect['database_port'] = 5432
praefect['database_user'] = 'praefect'
praefect['database_password'] = 'PRAEFECT_SQL_PASSWORD'
praefect['database_dbname'] = 'praefect_production'
```
# Replace PRAEFECT_EXTERNAL_TOKEN with a real secret
praefect['auth_token'] = 'PRAEFECT_EXTERNAL_TOKEN'
If you want to use a TLS client certificate, the options below can be used:
# Replace each instance of PRAEFECT_INTERNAL_TOKEN below with a real
# secret, distinct from PRAEFECT_EXTERNAL_TOKEN.
# Name of storage hash must match storage name in git_data_dirs on GitLab server.
praefect['virtual_storages'] = {
```ruby
# Connect to PostreSQL using a TLS client certificate
# praefect['database_sslcert'] = '/path/to/client-cert'
# praefect['database_sslkey'] = '/path/to/client-key'
# Trust a custom certificate authority
# praefect['database_sslrootcert'] = '/path/to/rootcert'
```
By default Praefect will refuse to make an unencrypted connection to
PostgreSQL. You can override this by uncommenting the following line:
```ruby
# praefect['database_sslmode'] = 'disable'
```
1. Configure the **Praefect** cluster to connect to each Gitaly node in the
cluster by editing `/etc/gitlab/gitlab.rb`.
In the example below we have configured one cluster named `praefect`. This
cluster has three Gitaly nodes `gitaly-1`, `gitaly-2`, and `gitaly-3`, which
will be replicas of each other.
Replace `PRAEFECT_INTERNAL_TOKEN` with a strong secret, which will be used by
Praefect when communicating with Gitaly nodes in the cluster. This token is
distinct from the `PRAEFECT_EXTERNAL_TOKEN`.
Replace `GITALY_HOST` with the IP/host address of the each Gitaly node.
More Gitaly nodes can be added to the cluster to increase the number of
replicas. More clusters can also be added for very large GitLab instances.
NOTE: **Note:** The `gitaly-1` node is currently denoted the primary. This
can be used to manually fail from one node to another. This will be removed
in the future to allow for automatic failover.
```ruby
# Name of storage hash must match storage name in git_data_dirs on GitLab
# server ('praefect') and in git_data_dirs on Gitaly nodes ('gitaly-1')
praefect['virtual_storages'] = {
'praefect' => {
'gitaly-1' => {
# Replace GITALY_URL_OR_IP below with the real address to connect to.
'address' => 'tcp://GITALY_URL_OR_IP:8075',
'address' => 'tcp://GITALY_HOST:8075',
'token' => 'PRAEFECT_INTERNAL_TOKEN',
'primary' => true
},
'gitaly-2' => {
# Replace GITALY_URL_OR_IP below with the real address to connect to.
'address' => 'tcp://GITALY_URL_OR_IP:8075',
'address' => 'tcp://GITALY_HOST:8075',
'token' => 'PRAEFECT_INTERNAL_TOKEN'
},
'gitaly-3' => {
# Replace GITALY_URL_OR_IP below with the real address to connect to.
'address' => 'tcp://GITALY_URL_OR_IP:8075',
'address' => 'tcp://GITALY_HOST:8075',
'token' => 'PRAEFECT_INTERNAL_TOKEN'
}
}
}
# Replace POSTGRESQL_SERVER below with a real IP/host address of the database.
praefect['database_host'] = 'POSTGRESQL_SERVER_ADDRESS'
praefect['database_port'] = 5432
praefect['database_user'] = 'praefect'
# Replace PRAEFECT_SQL_PASSWORD below with a real password of the database.
praefect['database_password'] = 'PRAEFECT_SQL_PASSWORD'
praefect['database_dbname'] = 'praefect_production'
# Uncomment the line below if you do not want to use an encrypted
# connection to PostgreSQL
# praefect['database_sslmode'] = 'disable'
# Uncomment and modify these lines if you are using a TLS client
# certificate to connect to PostgreSQL
# praefect['database_sslcert'] = '/path/to/client-cert'
# praefect['database_sslkey'] = '/path/to/client-key'
# Uncomment and modify this line if your PostgreSQL server uses a custom
# CA
# praefect['database_sslrootcert'] = '/path/to/rootcert'
```
}
```
Replace `POSTGRESQL_SERVER_ADDRESS`, `PRAEFECT_EXTERNAL_TOKEN`, `PRAEFECT_INTERNAL_TOKEN`,
and `PRAEFECT_SQL_PASSWORD` with their respective values.
1. Save the changes to `/etc/gitlab/gitlab.rb` and [reconfigure Praefect](../restart_gitlab.md#omnibus-gitlab-reconfigure):
Save the file and reconfigure Praefect:
```shell
sudo gitlab-ctl reconfigure
```
```shell
sudo gitlab-ctl reconfigure
```
1. Verify that Praefect can reach PostgreSQL:
After you reconfigure, verify that Praefect can reach PostgreSQL:
```shell
sudo -u git /opt/gitlab/embedded/bin/praefect -config /var/opt/gitlab/praefect/config.toml sql-ping
```
```shell
sudo -u git /opt/gitlab/embedded/bin/praefect -config /var/opt/gitlab/praefect/config.toml sql-ping
```
If the check fails, make sure you have followed the steps correctly. If you
edit `/etc/gitlab/gitlab.rb`, remember to run `sudo gitlab-ctl reconfigure`
again before trying the `sql-ping` command.
### Gitaly
NOTE: **Note:** Complete these steps for **each** Gitaly node.
To complete this section you will need:
- [Configured Praefect node](#praefect)
- 3 (or more) servers, with GitLab installed, to be configured as Gitaly nodes.
These should be dedicated nodes, do not run other services on these nodes.
Every Gitaly server assigned to the Praefect cluster needs to be configured. The
configuration is the same as a normal [standalone Gitaly server](../index.md),
except:
- the storage names are exposed to Praefect, not GitLab
- the secret token is shared with Praefect, not GitLab
The configuration of all Gitaly nodes in the Praefect cluster can be identical,
because we rely on Praefect to route operations correctly.
Particular attention should be shown to:
- the `gitaly['auth_token']` configured in this section must match the `token`
value under `praefect['virtual_storages']` on the Praefect node. This was set
in the [previous section](#praefect). This document uses the placeholder
`PRAEFECT_INTERNAL_TOKEN` throughout.
- the storage names in `git_data_dirs` configured in this section must match the
storage names under `praefect['virtual_storages']` on the Praefect node. This
was set in the [previous section](#praefect). This document uses `gitaly-1`,
`gitaly-2`, and `gitaly-3` as Gitaly storage names.
If the check fails, make sure you have followed the steps correctly. If you edit `/etc/gitlab/gitlab.rb`,
remember to run `sudo gitlab-ctl reconfigure` again before trying the
`sql-ping` command.
#### Gitaly
Next we will configure each Gitaly server assigned to Praefect. Configuration for these
is the same as a normal standalone Gitaly server, except that we use storage names and
auth tokens from Praefect instead of GitLab.
Below is an example configuration for `gitaly-1`, the only difference for the
other Gitaly nodes is the storage name under `git_data_dirs`.
Note that `gitaly['auth_token']` matches the `token` value listed under `praefect['virtual_storages']`
on the Praefect node.
```ruby
# /etc/gitlab/gitlab.rb on gitaly node inside praefect cluster
# Avoid running unnecessary services on the Gitaly server
postgresql['enable'] = false
redis['enable'] = false
nginx['enable'] = false
prometheus['enable'] = false
grafana['enable'] = false
unicorn['enable'] = false
sidekiq['enable'] = false
gitlab_workhorse['enable'] = false
prometheus_monitoring['enable'] = false
# Prevent database connections during 'gitlab-ctl reconfigure'
gitlab_rails['rake_cache_clear'] = false
gitlab_rails['auto_migrate'] = false
# Replace GITLAB_SHELL_SECRET_TOKEN below with real secret
gitlab_shell['secret_token'] = 'GITLAB_SHELL_SECRET_TOKEN'
# Configure the gitlab-shell API callback URL. Without this, `git push` will
# fail. This can be your 'front door' GitLab URL or an internal load
# balancer.
# Possible values could be: 'http://10.23.101.53', 'https://gitlab.example.com',
# etc. Please replace GITLAB_SERVER_ADDRESS with proper value and change schema
# to 'https' in case you use encrypted connection.
gitlab_rails['internal_api_url'] = 'http://GITLAB_SERVER_ADDRESS'
# Replace PRAEFECT_INTERNAL_TOKEN below with a real secret.
gitaly['auth_token'] = 'PRAEFECT_INTERNAL_TOKEN'
# Make Gitaly accept connections on all network interfaces. You must use
# firewalls to restrict access to this address/port.
# Comment out following line if you only want to support TLS connections
gitaly['listen_addr'] = "0.0.0.0:8075"
git_data_dirs({
# Update this to the name of this Gitaly server which will be later
# exposed in the UI under "Admin area > Gitaly"
For more information on Gitaly server configuration, see our [Gitaly
documentation](index.md#3-gitaly-server-configuration).
1. SSH into the **Gitaly** node and login as root:
```shell
sudo -i
```
1. Disable all other services by editing `/etc/gitlab/gitlab.rb`:
```ruby
# Disable all other services on the Praefect node
postgresql['enable'] = false
redis['enable'] = false
nginx['enable'] = false
prometheus['enable'] = false
grafana['enable'] = false
unicorn['enable'] = false
sidekiq['enable'] = false
gitlab_workhorse['enable'] = false
prometheus_monitoring['enable'] = false
# Enable only the Praefect service
gitaly['enable'] = true
# Prevent database connections during 'gitlab-ctl reconfigure'
gitlab_rails['rake_cache_clear'] = false
gitlab_rails['auto_migrate'] = false
```
1. Configure **Gitaly** to listen on network interfaces by editing
`/etc/gitlab/gitlab.rb`:
```ruby
# Make Gitaly accept connections on all network interfaces.
# Use firewalls to restrict access to this address/port.
gitaly['listen_addr'] = '0.0.0.0:8075'
```
1. Configure a strong `auth_token` for **Gitaly** by editing
`/etc/gitlab/gitlab.rb`. This will be needed by clients to communicate with
this Gitaly nodes. Typically, this token will be the same for all Gitaly
nodes.
```ruby
gitaly['auth_token'] = 'PRAEFECT_INTERNAL_TOKEN'
```
1. Configure the GitLab Shell `secret_token`, and `internal_api_url` which are
needed for `git push` operations.
If you have already configured [Gitaly on its own server](../index.md)
```ruby
gitlab_shell['secret_token'] = 'GITLAB_SHELL_SECRET_TOKEN'
# Configure the gitlab-shell API callback URL. Without this, `git push` will
# fail. This can be your front door GitLab URL or an internal load balancer.
# Examples: 'https://example.gitlab.com', 'http://1.2.3.4'
gitlab_rails['internal_api_url'] = 'GITLAB_SERVER_URL'
```
1. Configure the storage location for Git data by setting `git_data_dirs` in
`/etc/gitlab/gitlab.rb`. Each Gitaly node should have a unique storage name
(eg `gitaly-1`).
Instead of configuring `git_data_dirs` uniquely for each Gitaly node, it is
often easier to have include the configuration for all Gitaly nodes on every
Gitaly node. This is supported because the Praefect `virtual_storages`
configuration maps each storage name (eg `gitaly-1`) to a specific node, and
requests are routed accordingly. This means every Gitaly node in your fleet
can share the same configuration.
```ruby
# You can include the data dirs for all nodes in the same config, because
# Praefect will only route requests according to the addresses provided in the
# prior step.
git_data_dirs({
"gitaly-1" => {
"path" => "/var/opt/gitlab/git-data"
},
"gitaly-2" => {
"path" => "/var/opt/gitlab/git-data"
},
"gitaly-3" => {
"path" => "/var/opt/gitlab/git-data"
}
})
```
})
```
Replace `GITLAB_SHELL_SECRET_TOKEN` and `PRAEFECT_INTERNAL_TOKEN`
with their respective values.
1. Save the changes to `/etc/gitlab/gitlab.rb` and [reconfigure Gitaly](../restart_gitlab.md#omnibus-gitlab-reconfigure):
For more information on Gitaly server configuration, see our [Gitaly documentation](index.md#3-gitaly-server-configuration).
```shell
sudo gitlab-ctl reconfigure
```
When finished editing the configuration file for each Gitaly server, run the
reconfigure command to put changes into effect:
**Complete these steps for each Gitaly node!**
```shell
sudo gitlab-ctl reconfigure
```
When all Gitaly servers are configured, you can run the Praefect connection
After all Gitaly nodes are configured, you can run the Praefect connection
checker to verify Praefect can connect to all Gitaly servers in the Praefect
config. This can be done by running the following command on the Praefect
server:
config.
```shell
sudo /opt/gitlab/embedded/bin/praefect -config /var/opt/gitlab/praefect/config.toml dial-nodes
```
1. SSH into the **Praefect** node and run the Praefect connection checker:
```shell
sudo /opt/gitlab/embedded/bin/praefect -config /var/opt/gitlab/praefect/config.toml dial-nodes
```
### GitLab
To complete this section you will need:
- [Configured Praefect node](#praefect)
- [Configured Gitaly nodes](#gitaly)
The Praefect cluster needs to be exposed as a storage location to the GitLab
application. This is done by updating the `git_data_dirs`.
#### GitLab
Particular attention should be shown to:
When Praefect is running, it should be exposed as a storage to GitLab. This
is done through setting the `git_data_dirs`. Assuming the default storage
is present, there should be two storages available to GitLab:
- the storage name added to `git_data_dirs` in this section must match the
storage name under `praefect['virtual_storages']` on the Praefect node. This
was set in the [Praefect](#praefect) section of this guide. This document uses
`praefect` as the Praefect storage name.
```ruby
# /etc/gitlab/gitlab.rb on gitlab server
1. SSH into the **GitLab** node and login as root:
# Replace PRAEFECT_URL_OR_IP below with real address Praefect can be accessed at.
# Replace PRAEFECT_EXTERNAL_TOKEN below with real secret.
git_data_dirs({
```shell
sudo -i
```
1. Add the Praefect cluster as a storage location by editing
`/etc/gitlab/gitlab.rb`.
You will need to replace:
- `PRAEFECT_URL_OR_IP` with the IP/host address of the Praefect node
- `PRAEFECT_EXTERNAL_TOKEN` with the real secret
```ruby
git_data_dirs({
"default" => {
"path" => "/var/opt/gitlab/git-data"
},
......@@ -323,37 +465,61 @@ git_data_dirs({
"gitaly_address" => "tcp://PRAEFECT_URL_OR_IP:2305",
"gitaly_token" => 'PRAEFECT_EXTERNAL_TOKEN'
}
})
})
```
# Replace GITLAB_SHELL_SECRET_TOKEN below with real secret
gitlab_shell['secret_token'] = 'GITLAB_SHELL_SECRET_TOKEN'
1. Configure the `gitlab_shell['secret_token']` so that callbacks from Gitaly
nodes during a `git push` are properly authenticated by editing
`/etc/gitlab/gitlab.rb`:
# Possible values could be: 'http://10.23.101.53', 'https://gitlab.example.com',
# etc. Please replace GITLAB_SERVER_ADDRESS with proper value and change schema
# to 'https' in case you use encrypted connection. For more info please refer
# to https://docs.gitlab.com/omnibus/settings/configuration.html#configuring-the-external-url-for-gitlab
external_url "http://<GITLAB_SERVER_ADDRESS>"
```
You will need to replace `GITLAB_SHELL_SECRET_TOKEN` with the real secret.
Replace `GITLAB_SHELL_SECRET_TOKEN` and `PRAEFECT_EXTERNAL_TOKEN`
with their respective values.
```ruby
gitlab_shell['secret_token'] = 'GITLAB_SHELL_SECRET_TOKEN'
```
Note that the storage name used is the same as the `praefect['virtual_storage_name']` set
on the Praefect node.
1. Save the changes to `/etc/gitlab/gitlab.rb` and [reconfigure GitLab](../restart_gitlab.md#omnibus-gitlab-reconfigure):
Save your changes and reconfigure GitLab:
```shell
sudo gitlab-ctl reconfigure
```
```shell
sudo gitlab-ctl reconfigure
```
1. Verify that GitLab can reach Praefect:
```shell
sudo gitlab-rake gitlab:gitaly:check
```
1. Update the **Repository storage** settings from **Admin Area > Settings >
Repository > Repository storage** to make the newly configured Praefect
cluster the storage location for new Git repositories.
- Deselect the **default** storage location
- Select the **praefect** storage location
1. Verify everything is still working by creating a new project. Check the
"Initialize repository with a README" box so that there is content in the
repository that viewed. If the project is created, and you can see the
README file, it works!
Run `sudo gitlab-rake gitlab:gitaly:check` to confirm that GitLab can reach Praefect.
Congratulations! You have configured a highly available Praefect cluster, and
### Testing Praefect
## Migrating existing repositories to Praefect
If your GitLab instance already has repositories, these won't be migrated
automatically.
Repositories may be moved from one storage location using the [Repository
API](../../api/projects.html#edit-project):
```shell
curl --request PUT \
--header "PRIVATE-TOKEN: <your_access_token>" \
--data "repository_storage=praefect" \
https://example.gitlab.com/api/v4/projects/123
```
To test Praefect, first set it as the default storage node for new projects
using **Admin Area > Settings > Repository > Repository storage**. Next,
create a new project and check the "Initialize repository with a README" box.
## Debugging Praefect
If you receive an error, check `/var/log/gitlab/gitlab-rails/production.log`.
......
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