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Author SHA1 Message Date
pat-s 7eea1acf05 chore: reduce redis-cluster pods and move HA out of "experimental" state (#565)
The pod reduction for `redis-cluster` should help users seeking for a Gitea deployment with less pods. Users seeking for a minimal deployment are further advised to follow https://gitea.com/gitea/helm-chart#user-content-single-pod-configurations.

HA is working fine in the provided configuration and should be moved out of the "experimental" state given that there were no reports of Gitea malfunctioning reported to HA usage in recent months/since v9 release.

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/565
Reviewed-by: techknowlogick <techknowlogick@noreply.gitea.com>
Co-authored-by: pat-s <patrick.schratz@gmail.com>
Co-committed-by: pat-s <patrick.schratz@gmail.com>
2023-11-16 10:14:34 +00:00
pat-s 950e46ce44
add experimental note 2023-07-17 21:13:01 +02:00
pat-s 8e27bb9bae [Breaking] Add HA-support; switch to `Deployment` (#437)
# Changes

A big shoutout to @luhahn for all his work in #205 which served as the base for this PR.

## Documentation

- [x] After thinking for some time about it, I still prefer the distinct option (as started in #350), i.e. having a standalone "HA" doc under `docs/ha-setup.md` to not have a very long README (which is already quite long).
      Most of the information below should go into it with more details and explanations behind all of the individual components.

## Chart deps

~~- Adds `meilisearch` as a chart dependency for a HA-ready issue indexer. Only works with >= Gitea 1.20~~
~~- Adds `redis` as a chart dependency for a HA-ready session and queue store.~~
- Adds `redis-cluster` as a chart dependency for a HA-ready session and queue store (alternative to `redis`). Only works with >= Gitea 1.19.2.
- Removes `memcached` instead of `redis-cluster`
- Add `postgresql-ha` as default DB dep in favor of `postgres`

## Adds smart HA chart logic

The goal is to set smart config values that result in a HA-ready Gitea deployment if `replicaCount` > 1.

- If `replicaCount` > 1,
  - `gitea.config.session.PROVIDER` is automatically set to `redis-cluster`
  - `gitea.config.indexer.REPO_INDEXER_ENABLED` is automatically set to `false` unless the value is `elasticsearch` or `meilisearch`
  - `redis-cluster` is used for `[queue]` and `[cache]` and `[session]`mode or not

Configuration of external instances of `meilisearch` and `minio` are documented in a new markdown doc.

## Deployment vs Statefulset

Given all the discussions about this lately (#428), I think we could use both.
In the end, we do not have the requirement for a sequential pod scale up/scale down as it would happen in statefulsets.
On the other side, we do not have actual stateless pods as we are attaching a RWX to the deployment.
Yet I think because we do not have a leader-election requirement, spawning the pods as a deployment makes "Rolling Updates" easier and also signals users that there is no "leader election" logic and each pod can just be "destroyed" at anytime without causing interruption.

Hence I think we should be able to switch from a statefulset to a deployment, even in the single-replica case.

This change also brought up a templating/linting issue: the definition of `.Values.gitea.config.server.SSH_LISTEN_PORT` in `ssh-svc.yaml` just "luckily" worked so far due to naming-related lint processing. Due to the change from "statefulset" to "deployment", the processing queue changed and caused a failure complaining about `config.server.SSH_LISTEN_PORT` not being defined yet.
The only way I could see to fix this was to "properly" define the value in `values.yaml` instead of conditionally definining it in `helpers.tpl`. Maybe there's a better way?

## Chart PVC Creation

I've adapted the automated PVC creation from another chart to be able to provide the `storageClassName` as I couldn't get dynamic provisioning for EFS going with the current implementation.
In addition the naming and approach within the Gitea chart for PV creation is a bit unusual and aligning it might be beneficial.

A semi-unrelated change which will result in a breaking change for existing users but this PR includes a lot of breaking changes already, so including another one might not make it much worse...

- New `persistence.mount`: whether to mount an existing PVC (via `persistence.existingClaim`
- New `persistence.create`: whether to create a new PVC

## Testing

As this PR does a lot of things, we need proper testing.
The helm chart can be installed from the Git branch via `helm-git` as follows:

```
helm repo add gitea-charts git+https://gitea.com/gitea/helm-chart@/?ref=deployment
helm install gitea --version 0.0.0
```
It is **highly recommended** to test the chart in a dedicated namespace.

I've tested this myself with both `redis` and `redis-cluster` and it seemed to work fine.
I just did some basic operations though and we should do more niche testing before merging.

Examplary `values.yml` for testing (only needs a valid RWX storage class):

<details>

<summary>values.yaml</summary>

```yml
image:
  tag: "dev"
  PullPolicy: "Always"
  rootless: true

replicaCount: 2

persistence:
  enabled: true
  accessModes:
    - ReadWriteMany
  storageClass: FIXME

redis-cluster:
  enabled: false
  global:
    redis:
      password: gitea

gitea:
  config:
    indexer:
      ISSUE_INDEXER_ENABLED: true
      REPO_INDEXER_ENABLED: false
```
</details>

## Preferred setup

The preferred HA setup with respect to performance and stability might currently be as follows:

- Repos: RWX (e.g. EFS or Azurefiles NFS)
- Issue indexer: Meilisearch (HA)
- Session and cache: Redis Cluster (HA)
- Attachments/Avatars: Minio (HA)

This will result in a ~ 10-pod HA setup overall.
All pods have very low resource requests.

fix #98

Co-authored-by: pat-s <pat-s@noreply.gitea.io>
Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/437
Co-authored-by: pat-s <patrick.schratz@gmail.com>
Co-committed-by: pat-s <patrick.schratz@gmail.com>
2023-07-17 19:09:42 +00:00