178 lines
8.1 KiB
Markdown
178 lines
8.1 KiB
Markdown
# High Availability
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All components (in-memory DB, volume/asset storage, code indexer) used by Gitea must be deployed in a HA-ready fashion to achieve a full HA-ready Gitea deployment.
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The following document explains how to achieve this for all individual components.
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The resulting Gitea deployment will consist of ~ 10 pods (depending on the chosen components and their replicas).
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One should evaluate upfront whether a HA-deployment is required as switching between HA/non-HA comes with some effort.
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For production instances, HA is always recommended to increase uptime and have a frictionless update process.
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A general comment about chart dependencies and external services:
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Instead of relying on chart dependencies, it is often better to rely on an external, (managed) instances (in-memory database, asset storage provider, database, etc.).
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Many cloud providers offer such services, at least for databases or in-memory databases.
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They might cost a bit more than using a self-hosted k8s variant but are usually easier to maintain and scale, if needed.
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Also they can be centrally managed and are not linked to the Gitea helm chart or namespace.
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Please consider using external services before you start with your Gitea HA setup, it will make your life (and the life of the Gitea maintainers) easier.
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This helm chart tries to help as much as possible to simplify and assert the provisioning of a HA-ready Gitea instance by implementing smart conditionals if `replicaCount` is set to a value > 1.
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Nevertheless, we cannot guarantee for every possible combination of Gitea settings to work together perfectly in a HA setup.
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As a general advice, we recommend to have a test environment aside on which to test possible changes/upgrades before applying these to a production installation.
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## Requirements for HA
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Storage-wise, the HA-Gitea setup requires a RWX file-system which can be shared among the deployment-based replica pods.
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In addition, the following components are required for full HA-readiness:
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- A HA-ready issue (and optionally code) indexer: `elasticsearch` or `meilisearch`
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- A HA-ready external object/asset storage (`minio`) (optional, assets can also be stored on the RWX file-system)
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- A HA-ready cache (`redis-cluster`)
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- A HA-ready DB
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`postgres.enabled`, which default to `true`, must be set to `false` for a HA setup.
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The default `postgres` chart dependency is not HA-ready (there's a dedicated `postgres-ha` chart).
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The following sections discuss each of the components in more detail.
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Note that for each component discussed, the shown configurations only provides a (working) starting point, not necessarily the most optimal setup.
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We try to optimize this document over time as we have gained more experience with HA setups from users.
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## Indexers (Issues and code/repo)
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The default code indexer `bleve` is not able to allow multiple connections and hence cannot be used in a HA setup.
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Alternatives are `elasticsearch` and `meilisearch` (as of >= 1.19.2).
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Unless you have an existing `elasticsearch` cluster, we recommend using `meilisearch` as it is faster and requires way less resources.
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Unfortunately, `meilisearch` does only support the `ISSUE_INDEXER` and not the `REPO_INDEXER` yet ([tracking issue](https://github.com/go-gitea/gitea/pull/24149)).
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This means that the `REPO_INDEXER` must still be disabled for a HA setup right now.
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An alternative to the two options above for the `ISSUE_INDEXER` is `"db"`, however we recommend to just go with `meilisearch` in this case and to not bother the DB with indexing.
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To configure `meilisearch` within Gitea, do the following:
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```yml
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gitea:
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config:
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indexer:
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ISSUE_INDEXER_CONN_STR: <http://meilisearch.<namespace>.svc.cluster.local:7700>
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ISSUE_INDEXER_ENABLED: true
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ISSUE_INDEXER_TYPE: meilisearch
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REPO_INDEXER_ENABLED: false
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# REPO_INDEXER_TYPE: meilisearch # not yet working
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```
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Unfortunately `meilisearch` cannot be deployed in HA as of now.
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Nevertheless it allows for multiple Gitea requests at the same time and is therefore required in a HA setup.
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Exemplary configuration for the [meilisearch-kubernetes](https://github.com/meilisearch/meilisearch-kubernetes/tree/main/charts/meilisearch) chart:
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```yaml
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persistence:
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enabled: true
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accessMode: ReadWriteOnce
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size: 5Gi
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```
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## Cache, session and queue
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A `redis` instance is required for the in-memory cache.
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Two options exist:
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- `redis`
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- `redis-cluster`
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The chart provides `redis-cluster` as a dependency as this one can be used for both HA and non-HA setups.
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You're also welcome to go with `redis` if you prefer or already have a running instance.
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It should be noted that `redis-cluster` support is only available starting with Gitea 1.19.2.
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You can also configure an external (managed) `redis` instance to be used.
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To do so, you need to set the following configuration values yourself:
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- `gitea.config.queue.TYPE`: redis`
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- `gitea.config.queue.CONN_STR`: `<your redis connection string>`
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- `gitea.config.session.PROVIDER`: `redis`
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- `gitea.config.session.PROVIDER_CONFIG`: `<your redis connection string>`
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- `gitea.config.cache.ENABLED`: `true`
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- `gitea.config.cache.ADAPTER`: `redis`
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- `gitea.config.cache.HOST`: `<your redis connection string>`
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By default, the `redis-cluster` chart provisions three standalone master nodes of which each has a single replica.
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To reduce the number of pods for a default Gitea deployment, we opted to omit the replicas (`replicas: 0`) by default.
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Only the minimum required number of master pods for a functional `redis-cluster` deployment are provisioned.
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For a "proper" `redis-cluster` setup however, we recommend to set `replicas: 1` and `nodes: 6`.
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## Object and asset storage
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Object/asset storage refers to the storage of attachments, avatars, LFS files, etc.
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While most of these can be stored on the RWX file-system, it is recommended to use an external S3-compatible object storage for such, mainly for performance reasons.
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By default the chart provisions a single RWO volume to store everything (repos, avatars, packages, etc.).
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This volume cannot be mounted by multiple pods.
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Hence, a RWX volume is required and (optionally) an external HA-ready object storage.
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> **Note:** Double-check that the file permissions are set correctly on the RWX volume! That is everything should be owned by the `git` user which usually has `uid=1000` and `gid=1000`.
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To use `minio` you need to deploy and configure an external `minio` instance yourself and explicitly define the `STORAGE_TYPE` values as shown below.
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Note that `MINIO_BUCKET` here is just a name and does not refer to a S3 bucket.
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It's the root access point for all objects belonging to the respective application, i.e., to Gitea in this case.
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```yaml
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gitea:
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config:
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attachment:
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STORAGE_TYPE: minio
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lfs:
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STORAGE_TYPE: minio
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picture:
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AVATAR_STORAGE_TYPE: minio
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"storage.packages":
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STORAGE_TYPE: minio
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storage:
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MINIO_ENDPOINT: <minio-headless.<namespace>.svc.cluster.local:9000>
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MINIO_LOCATION: <location>
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MINIO_ACCESS_KEY_ID: <access key>
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MINIO_SECRET_ACCESS_KEY: <secret key>
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MINIO_BUCKET: <bucket name>
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MINIO_USE_SSL: false
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```
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Exemplary configuration for the [bitnami minio](https://github.com/bitnami/charts/blob/main/bitnami/minio) chart:
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```yaml
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auth:
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rootUser: minio
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mode: distributed
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replicaCount: 4
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persistence:
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enabled: true
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size: 20Gi
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accessModes:
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- ReadWriteOnce
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```
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## Database
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If you do not have an HA-ready DB, using a managed database service in the cloud might be the easiest and most robust solution.
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Remember: disable the built-in `postgres` dependency and configure the database connection manually via `gitea.config.database`:
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```yml
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gitea:
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database:
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builtIn:
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postgresql:
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enabled: false
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config:
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database:
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DB_TYPE: postgres
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HOST: <host>
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NAME: <name>
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USER: <user>
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```
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## Known issues
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- Currently Cron jobs are run on all replicas as no leader election is implemented.
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See [https://github.com/go-gitea/gitea/issues/13791](https://github.com/go-gitea/gitea/issues/13791) for a discussion and possible solution.
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- Running with multiple replicas slows down Gitea a bit, i.e. page loading time increases. |