467 lines
24 KiB
Markdown
467 lines
24 KiB
Markdown
---
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stage: none
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group: unassigned
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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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# Review Apps
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Review Apps are deployed using the `start-review-app-pipeline` job. This job triggers a child pipeline containing a series of jobs to perform the various tasks needed to deploy a Review App.
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![start-review-app-pipeline job](img/review-app-parent-pipeline.png)
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For any of the following scenarios, the `start-review-app-pipeline` job would be automatically started:
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- for merge requests with CI config changes
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- for merge requests with frontend changes
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- for merge requests with changes to `{,ee/,jh/}{app/controllers}/**/*`
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- for merge requests with changes to `{,ee/,jh/}{app/models}/**/*`
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- for merge requests with QA changes
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- for scheduled pipelines
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- the MR has the `pipeline:run-review-app` label set
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## QA runs on Review Apps
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On every [pipeline](https://gitlab.com/gitlab-org/gitlab/pipelines/125315730) in the `qa` stage (which comes after the
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`review` stage), the `review-qa-smoke` and `review-qa-reliable` jobs are automatically started. The `review-qa-smoke` runs
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the QA smoke suite and the `review-qa-reliable` executes E2E tests identified as [reliable](https://about.gitlab.com/handbook/engineering/quality/quality-engineering/reliable-tests).
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You can also manually start the `review-qa-all`: it runs the full QA suite.
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After the end-to-end test runs have finished, [Allure reports](https://github.com/allure-framework/allure2) are generated and published by
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the `allure-report-qa-smoke`, `allure-report-qa-reliable`, and `allure-report-qa-all` jobs. A comment with links to the reports are added to the merge request.
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Errors can be found in the `gitlab-review-apps` Sentry project and [filterable by Review App URL](https://sentry.gitlab.net/gitlab/gitlab-review-apps/?query=url%3A%22https%3A%2F%2Fgitlab-review-require-ve-u92nn2.gitlab-review.app%2F%22) or [commit SHA](https://sentry.gitlab.net/gitlab/gitlab-review-apps/releases/6095b501da7/all-events/).
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## Performance Metrics
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On every [pipeline](https://gitlab.com/gitlab-org/gitlab/pipelines/125315730) in the `qa` stage, the
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`review-performance` job is automatically started: this job does basic
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browser performance testing using a
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[Sitespeed.io Container](../../user/project/merge_requests/browser_performance_testing.md).
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## Sample Data for Review Apps
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Upon deployment of a review app, project data is created from the [`sample-gitlab-project`](https://gitlab.com/gitlab-org/sample-data-templates/sample-gitlab-project) template project. This aims to provide projects with prepopulated resources to facilitate manual and exploratory testing.
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The sample projects will be created in the `root` user namespace and can be accessed from the personal projects list for that user.
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## How to
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### Redeploy Review App from a clean slate
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To reset Review App and redeploy from a clean slate, do the following:
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1. Run `review-stop` job.
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1. Re-deploy by running or retrying `review-deploy` job.
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Doing this will remove all existing data from a previously deployed Review App.
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### Get access to the GCP Review Apps cluster
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You need to [open an access request (internal link)](https://gitlab.com/gitlab-com/access-requests/-/issues/new)
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for the `gcp-review-apps-dev` GCP group and role.
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This grants you the following permissions for:
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- [Retrieving pod logs](#dig-into-a-pods-logs). Granted by [Viewer (`roles/viewer`)](https://cloud.google.com/iam/docs/understanding-roles#kubernetes-engine-roles).
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- [Running a Rails console](#run-a-rails-console). Granted by [Kubernetes Engine Developer (`roles/container.pods.exec`)](https://cloud.google.com/iam/docs/understanding-roles#kubernetes-engine-roles).
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### Log into my Review App
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For GitLab Team Members only. If you want to sign in to the review app, review
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the GitLab handbook information for the [shared 1Password account](https://about.gitlab.com/handbook/security/#1password-for-teams).
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- The default username is `root`.
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- The password can be found in the 1Password login item named `GitLab EE Review App`.
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### Enable a feature flag for my Review App
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1. Open your Review App and log in as documented above.
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1. Create a personal access token.
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1. Enable the feature flag using the [Feature flag API](../../api/features.md).
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### Find my Review App slug
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1. Open the `review-deploy` job.
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1. Look for `** Deploying review-*`.
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1. For instance for `** Deploying review-1234-abc-defg... **`,
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your Review App slug would be `review-1234-abc-defg` in this case.
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### Run a Rails console
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1. Make sure you [have access to the cluster](#get-access-to-the-gcp-review-apps-cluster) and the `container.pods.exec` permission first.
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1. [Filter Workloads by your Review App slug](https://console.cloud.google.com/kubernetes/workload?project=gitlab-review-apps). For example, `review-qa-raise-e-12chm0`.
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1. Find and open the `toolbox` Deployment. For example, `review-qa-raise-e-12chm0-toolbox`.
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1. Click on the Pod in the "Managed pods" section. For example, `review-qa-raise-e-12chm0-toolbox-d5455cc8-2lsvz`.
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1. Click on the `KUBECTL` dropdown, then `Exec` -> `toolbox`.
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1. Replace `-c toolbox -- ls` with `-it -- gitlab-rails console` from the
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default command or
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- Run `kubectl exec --namespace review-qa-raise-e-12chm0 review-qa-raise-e-12chm0-toolbox-d5455cc8-2lsvz -it -- gitlab-rails console` and
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- Replace `review-qa-raise-e-12chm0-toolbox-d5455cc8-2lsvz`
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with your Pod's name.
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### Dig into a Pod's logs
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1. Make sure you [have access to the cluster](#get-access-to-the-gcp-review-apps-cluster) and the `container.pods.getLogs` permission first.
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1. [Filter Workloads by your Review App slug](https://console.cloud.google.com/kubernetes/workload?project=gitlab-review-apps). For example, `review-qa-raise-e-12chm0`.
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1. Find and open the `migrations` Deployment. For example, `review-qa-raise-e-12chm0-migrations.1`.
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1. Click on the Pod in the "Managed pods" section. For example, `review-qa-raise-e-12chm0-migrations.1-nqwtx`.
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1. Click on the `Container logs` link.
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Alternatively, you could use the [Logs Explorer](https://console.cloud.google.com/logs/query;query=?project=gitlab-review-apps) which provides more utility to search logs. An example query for a pod name is as follows:
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```shell
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resource.labels.pod_name:"review-qa-raise-e-12chm0-migrations"
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```
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## How does it work?
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### CI/CD architecture diagram
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```mermaid
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graph TD
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A["build-qa-image, compile-production-assets<br/>(canonical default refs only)"];
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B[review-build-cng];
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C[review-deploy];
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D[CNG-mirror];
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E[review-qa-smoke, review-qa-reliable];
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A -->|once the `prepare` stage is done| B
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B -.->|triggers a CNG-mirror pipeline and wait for it to be done| D
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D -.->|polls until completed| B
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B -->|once the `review-build-cng` job is done| C
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C -->|once the `review-deploy` job is done| E
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subgraph "1. gitlab `prepare` stage"
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A
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end
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subgraph "2. gitlab `review-prepare` stage"
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B
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end
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subgraph "3. gitlab `review` stage"
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C["review-deploy<br><br>Helm deploys the Review App using the Cloud<br/>Native images built by the CNG-mirror pipeline.<br><br>Cloud Native images are deployed to the `review-apps`<br>Kubernetes (GKE) cluster, in the GCP `gitlab-review-apps` project."]
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end
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subgraph "4. gitlab `qa` stage"
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E[review-qa-smoke, review-qa-reliable<br><br>gitlab-qa runs the smoke and reliable suites against the Review App.]
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end
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subgraph "CNG-mirror pipeline"
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D>Cloud Native images are built];
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end
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```
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### Detailed explanation
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1. On every [pipeline](https://gitlab.com/gitlab-org/gitlab/pipelines/125315730) during the `prepare` stage, the
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[`compile-production-assets`](https://gitlab.com/gitlab-org/gitlab/-/jobs/641770154) job is automatically started.
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- Once it's done, the [`review-build-cng`](https://gitlab.com/gitlab-org/gitlab/-/jobs/467724808)
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job starts since the [`CNG-mirror`](https://gitlab.com/gitlab-org/build/CNG-mirror) pipeline triggered in the
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following step depends on it.
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1. Once `compile-production-assets` is done, the [`review-build-cng`](https://gitlab.com/gitlab-org/gitlab/-/jobs/467724808)
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job [triggers a pipeline](https://gitlab.com/gitlab-org/build/CNG-mirror/pipelines/44364657)
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in the [`CNG-mirror`](https://gitlab.com/gitlab-org/build/CNG-mirror) project.
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- The `review-build-cng` job automatically starts only if your MR includes
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[CI or frontend changes](../pipelines.md#changes-patterns). In other cases, the job is manual.
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- The [`CNG-mirror`](https://gitlab.com/gitlab-org/build/CNG-mirror/pipelines/44364657) pipeline creates the Docker images of
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each component (for example, `gitlab-rails-ee`, `gitlab-shell`, `gitaly` etc.)
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based on the commit from the [GitLab pipeline](https://gitlab.com/gitlab-org/gitlab/pipelines/125315730) and stores
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them in its [registry](https://gitlab.com/gitlab-org/build/CNG-mirror/container_registry).
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- We use the [`CNG-mirror`](https://gitlab.com/gitlab-org/build/CNG-mirror) project so that the `CNG`, (Cloud
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Native GitLab), project's registry is not overloaded with a lot of transient Docker images.
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- Note that the official CNG images are built by the `cloud-native-image`
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job, which runs only for tags, and triggers itself a [`CNG`](https://gitlab.com/gitlab-org/build/CNG) pipeline.
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1. Once `review-build-cng` is done, the [`review-deploy`](https://gitlab.com/gitlab-org/gitlab/-/jobs/467724810) job
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deploys the Review App using [the official GitLab Helm chart](https://gitlab.com/gitlab-org/charts/gitlab/) to
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the [`review-apps`](https://console.cloud.google.com/kubernetes/clusters/details/us-central1-b/review-apps?project=gitlab-review-apps)
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Kubernetes cluster on GCP.
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- The actual scripts used to deploy the Review App can be found at
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[`scripts/review_apps/review-apps.sh`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/scripts/review_apps/review-apps.sh).
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- These scripts are basically
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[our official Auto DevOps scripts](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/ci/templates/Auto-DevOps.gitlab-ci.yml) where the
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default CNG images are overridden with the images built and stored in the
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[`CNG-mirror` project's registry](https://gitlab.com/gitlab-org/build/CNG-mirror/container_registry).
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- Since we're using [the official GitLab Helm chart](https://gitlab.com/gitlab-org/charts/gitlab/), this means
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you get a dedicated environment for your branch that's very close to what
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it would look in production.
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- Each review app is deployed to its own Kubernetes namespace. The namespace is based on the Review App slug that is
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unique to each branch.
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1. Once the [`review-deploy`](https://gitlab.com/gitlab-org/gitlab/-/jobs/467724810) job succeeds, you should be able to
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use your Review App thanks to the direct link to it from the MR widget. To log
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into the Review App, see "Log into my Review App?" below.
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**Additional notes:**
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- If the `review-deploy` job keeps failing (and a manual retry didn't help),
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please post a message in the `#g_qe_engineering_productivity` channel and/or create a `~"Engineering Productivity"` `~"ep::review apps"` `~"type::bug"`
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issue with a link to your merge request. Note that the deployment failure can
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reveal an actual problem introduced in your merge request (that is, this isn't
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necessarily a transient failure)!
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- If the `review-qa-smoke` or `review-qa-reliable` job keeps failing (note that we already retry them once),
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please check the job's logs: you could discover an actual problem introduced in
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your merge request. You can also download the artifacts to see screenshots of
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the page at the time the failures occurred. If you don't find the cause of the
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failure or if it seems unrelated to your change, please post a message in the
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`#quality` channel and/or create a ~Quality ~"type::bug" issue with a link to your
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merge request.
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- The manual `review-stop` can be used to
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stop a Review App manually, and is also started by GitLab once a merge
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request's branch is deleted after being merged.
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- The Kubernetes cluster is connected to the `gitlab` projects using the
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[GitLab Kubernetes integration](../../user/infrastructure/clusters/index.md). This basically
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allows to have a link to the Review App directly from the merge request widget.
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### Auto-stopping of Review Apps
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Review Apps are automatically stopped 2 days after the last deployment thanks to
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the [Environment auto-stop](../../ci/environments/index.md#stop-an-environment-after-a-certain-time-period) feature.
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If you need your Review App to stay up for a longer time, you can
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[pin its environment](../../ci/environments/index.md#override-a-deployments-scheduled-stop-time) or retry the
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`review-deploy` job to update the "latest deployed at" time.
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The `review-cleanup` job that automatically runs in scheduled
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pipelines (and is manual in merge request) stops stale Review Apps after 5 days,
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deletes their environment after 6 days, and cleans up any dangling Helm releases
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and Kubernetes resources after 7 days.
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The `review-gcp-cleanup` job that automatically runs in scheduled pipelines
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(and is manual in merge request) removes any dangling GCP network resources
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that were not removed along with the Kubernetes resources.
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## Cluster configuration
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The cluster is configured via Terraform in the [`engineering-productivity-infrastructure`](https://gitlab.com/gitlab-org/quality/engineering-productivity-infrastructure) project.
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Node pool image type must be `Container-Optimized OS (cos)`, not `Container-Optimized OS with Containerd (cos_containerd)`,
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due to this [known issue on the Kubernetes executor for GitLab Runner](https://gitlab.com/gitlab-org/gitlab-runner/-/issues/4755)
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### Helm
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The Helm version used is defined in the
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[`registry.gitlab.com/gitlab-org/gitlab-build-images:gitlab-helm3-kubectl1.14` image](https://gitlab.com/gitlab-org/gitlab-build-images/-/blob/master/Dockerfile.gitlab-helm3-kubectl1.14#L7)
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used by the `review-deploy` and `review-stop` jobs.
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## Diagnosing unhealthy Review App releases
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If [Review App Stability](https://app.periscopedata.com/app/gitlab/496118/Engineering-Productivity-Sandbox?widget=6690556&udv=785399)
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dips this may be a signal that the `review-apps` cluster is unhealthy.
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Leading indicators may be health check failures leading to restarts or majority failure for Review App deployments.
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The [Review Apps Overview dashboard](https://console.cloud.google.com/monitoring/classic/dashboards/6798952013815386466?project=gitlab-review-apps&timeDomain=1d)
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aids in identifying load spikes on the cluster, and if nodes are problematic or the entire cluster is trending towards unhealthy.
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### Database related errors in `review-deploy`, `review-qa-smoke`, or `review-qa-reliable`
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Occasionally the state of a Review App's database could diverge from the database schema. This could be caused by
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changes to migration files or schema, such as a migration being renamed or deleted. This typically manifests in migration errors such as:
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- migration job failing with a column that already exists
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- migration job failing with a column that does not exist
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To recover from this, please attempt to [redeploy Review App from a clean slate](#redeploy-review-app-from-a-clean-slate)
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### Release failed with `ImagePullBackOff`
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**Potential cause:**
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If you see an `ImagePullBackoff` status, check for a missing Docker image.
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**Where to look for further debugging:**
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To check that the Docker images were created, run the following Docker command:
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```shell
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`DOCKER_CLI_EXPERIMENTAL=enabled docker manifest repository:tag`
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```
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The output of this command indicates if the Docker image exists. For example:
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```shell
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DOCKER_CLI_EXPERIMENTAL=enabled docker manifest inspect registry.gitlab.com/gitlab-org/build/cng-mirror/gitlab-rails-ee:39467-allow-a-release-s-associated-milestones-to-be-edited-thro
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```
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If the Docker image does not exist:
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- Verify the `image.repository` and `image.tag` options in the `helm upgrade --install` command match the repository names used by CNG-mirror pipeline.
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- Look further in the corresponding downstream CNG-mirror pipeline in `review-build-cng` job.
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### Node count is always increasing (never stabilizing or decreasing)
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**Potential cause:**
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That could be a sign that the `review-cleanup` job is
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failing to cleanup stale Review Apps and Kubernetes resources.
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**Where to look for further debugging:**
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Look at the latest `review-cleanup` job log, and identify look for any
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unexpected failure.
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### p99 CPU utilization is at 100% for most of the nodes and/or many components
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**Potential cause:**
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This could be a sign that Helm is failing to deploy Review Apps. When Helm has a
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lot of `FAILED` releases, it seems that the CPU utilization is increasing, probably
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due to Helm or Kubernetes trying to recreate the components.
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**Where to look for further debugging:**
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Look at a recent `review-deploy` job log.
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**Useful commands:**
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```shell
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# Identify if node spikes are common or load on specific nodes which may get rebalanced by the Kubernetes scheduler
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kubectl top nodes | sort --key 3 --numeric
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# Identify pods under heavy CPU load
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kubectl top pods | sort --key 2 --numeric
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```
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### The `logging/user/events/FailedMount` chart is going up
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**Potential cause:**
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This could be a sign that there are too many stale secrets and/or configuration maps.
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**Where to look for further debugging:**
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Look at [the list of Configurations](https://console.cloud.google.com/kubernetes/config?project=gitlab-review-apps)
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or `kubectl get secret,cm --sort-by='{.metadata.creationTimestamp}' | grep 'review-'`.
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Any secrets or configuration maps older than 5 days are suspect and should be deleted.
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**Useful commands:**
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```shell
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# List secrets and config maps ordered by created date
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kubectl get secret,cm --sort-by='{.metadata.creationTimestamp}' | grep 'review-'
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# Delete all secrets that are 5 to 9 days old
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kubectl get secret --sort-by='{.metadata.creationTimestamp}' | grep '^review-' | grep '[5-9]d$' | cut -d' ' -f1 | xargs kubectl delete secret
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# Delete all secrets that are 10 to 99 days old
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kubectl get secret --sort-by='{.metadata.creationTimestamp}' | grep '^review-' | grep '[1-9][0-9]d$' | cut -d' ' -f1 | xargs kubectl delete secret
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# Delete all config maps that are 5 to 9 days old
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kubectl get cm --sort-by='{.metadata.creationTimestamp}' | grep 'review-' | grep -v 'dns-gitlab-review-app' | grep '[5-9]d$' | cut -d' ' -f1 | xargs kubectl delete cm
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# Delete all config maps that are 10 to 99 days old
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kubectl get cm --sort-by='{.metadata.creationTimestamp}' | grep 'review-' | grep -v 'dns-gitlab-review-app' | grep '[1-9][0-9]d$' | cut -d' ' -f1 | xargs kubectl delete cm
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```
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### Using K9s
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[K9s](https://github.com/derailed/k9s) is a powerful command line dashboard which allows you to filter by labels. This can help identify trends with apps exceeding the [review-app resource requests](https://gitlab.com/gitlab-org/gitlab/-/blob/master/scripts/review_apps/base-config.yaml). Kubernetes schedules pods to nodes based on resource requests and allow for CPU usage up to the limits.
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- In K9s you can sort or add filters by typing the `/` character
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- `-lrelease=<review-app-slug>` - filters down to all pods for a release. This aids in determining what is having issues in a single deployment
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- `-lapp=<app>` - filters down to all pods for a specific app. This aids in determining resource usage by app.
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- You can scroll to a Kubernetes resource and hit `d`(describe), `s`(shell), `l`(logs) for a deeper inspection
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![K9s](img/k9s.png)
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### Troubleshoot a pending `dns-gitlab-review-app-external-dns` Deployment
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#### Finding the problem
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|
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[In the past](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/62834), it happened
|
|
that the `dns-gitlab-review-app-external-dns` Deployment was in a pending state,
|
|
effectively preventing all the Review Apps from getting a DNS record assigned,
|
|
making them unreachable via domain name.
|
|
|
|
This in turn prevented other components of the Review App to properly start
|
|
(for example, `gitlab-runner`).
|
|
|
|
After some digging, we found that new mounts fail when performed
|
|
with transient scopes (for example, pods) of `systemd-mount`:
|
|
|
|
```plaintext
|
|
MountVolume.SetUp failed for volume "dns-gitlab-review-app-external-dns-token-sj5jm" : mount failed: exit status 1
|
|
Mounting command: systemd-run
|
|
Mounting arguments: --description=Kubernetes transient mount for /var/lib/kubelet/pods/06add1c3-87b4-11e9-80a9-42010a800107/volumes/kubernetes.io~secret/dns-gitlab-review-app-external-dns-token-sj5jm --scope -- mount -t tmpfs tmpfs /var/lib/kubelet/pods/06add1c3-87b4-11e9-80a9-42010a800107/volumes/kubernetes.io~secret/dns-gitlab-review-app-external-dns-token-sj5jm
|
|
Output: Failed to start transient scope unit: Connection timed out
|
|
```
|
|
|
|
This probably happened because the GitLab chart creates 67 resources, leading to
|
|
a lot of mount points being created on the underlying GCP node.
|
|
|
|
The [underlying issue seems to be a `systemd` bug](https://github.com/kubernetes/kubernetes/issues/57345#issuecomment-359068048)
|
|
that was fixed in `systemd` `v237`. Unfortunately, our GCP nodes are currently
|
|
using `v232`.
|
|
|
|
For the record, the debugging steps to find out this issue were:
|
|
|
|
1. Switch kubectl context to `review-apps-ce` (we recommend using [`kubectx`](https://github.com/ahmetb/kubectx/))
|
|
1. `kubectl get pods | grep dns`
|
|
1. `kubectl describe pod <pod name>` & confirm exact error message
|
|
1. Web search for exact error message, following rabbit hole to [a relevant Kubernetes bug report](https://github.com/kubernetes/kubernetes/issues/57345)
|
|
1. Access the node over SSH via the GCP console (**Computer Engine > VM
|
|
instances** then click the "SSH" button for the node where the `dns-gitlab-review-app-external-dns` pod runs)
|
|
1. In the node: `systemctl --version` => `systemd 232`
|
|
1. Gather some more information:
|
|
- `mount | grep kube | wc -l` (returns a count, for example, 290)
|
|
- `systemctl list-units --all | grep -i var-lib-kube | wc -l` (returns a count, for example, 142)
|
|
1. Check how many pods are in a bad state:
|
|
- Get all pods running a given node: `kubectl get pods --field-selector=spec.nodeName=NODE_NAME`
|
|
- Get all the `Running` pods on a given node: `kubectl get pods --field-selector=spec.nodeName=NODE_NAME | grep Running`
|
|
- Get all the pods in a bad state on a given node: `kubectl get pods --field-selector=spec.nodeName=NODE_NAME | grep -v 'Running' | grep -v 'Completed'`
|
|
|
|
#### Solving the problem
|
|
|
|
To resolve the problem, we needed to (forcibly) drain some nodes:
|
|
|
|
1. Try a normal drain on the node where the `dns-gitlab-review-app-external-dns`
|
|
pod runs so that Kubernetes automatically move it to another node: `kubectl drain NODE_NAME`
|
|
1. If that doesn't work, you can also perform a forcible "drain" the node by removing all pods: `kubectl delete pods --field-selector=spec.nodeName=NODE_NAME`
|
|
1. In the node:
|
|
- Perform `systemctl daemon-reload` to remove the dead/inactive units
|
|
- If that doesn't solve the problem, perform a hard reboot: `sudo systemctl reboot`
|
|
1. Uncordon any cordoned nodes: `kubectl uncordon NODE_NAME`
|
|
|
|
In parallel, since most Review Apps were in a broken state, we deleted them to
|
|
clean up the list of non-`Running` pods.
|
|
Following is a command to delete Review Apps based on their last deployment date
|
|
(current date was June 6th at the time) with
|
|
|
|
```shell
|
|
helm ls -d | grep "Jun 4" | cut -f1 | xargs helm delete --purge
|
|
```
|
|
|
|
#### Mitigation steps taken to avoid this problem in the future
|
|
|
|
We've created a new node pool with smaller machines to reduce the risk
|
|
that a machine reaches the "too many mount points" problem in the future.
|
|
|
|
## Frequently Asked Questions
|
|
|
|
**Isn't it too much to trigger CNG image builds on every test run? This creates
|
|
thousands of unused Docker images.**
|
|
|
|
> We have to start somewhere and improve later. Also, we're using the
|
|
> CNG-mirror project to store these Docker images so that we can just wipe out
|
|
> the registry at some point, and use a new fresh, empty one.
|
|
|
|
**How do we secure this from abuse? Apps are open to the world so we need to
|
|
find a way to limit it to only us.**
|
|
|
|
> This isn't enabled for forks.
|
|
|
|
## Other resources
|
|
|
|
- [Review Apps integration for CE/EE (presentation)](https://docs.google.com/presentation/d/1QPLr6FO4LduROU8pQIPkX1yfGvD13GEJIBOenqoKxR8/edit?usp=sharing)
|
|
- [Stability issues](https://gitlab.com/gitlab-org/quality/team-tasks/-/issues/212)
|
|
|
|
### Helpful command line tools
|
|
|
|
- [K9s](https://github.com/derailed/k9s) - enables CLI dashboard across pods and enabling filtering by labels
|
|
- [Stern](https://github.com/wercker/stern) - enables cross pod log tailing based on label/field selectors
|
|
|
|
---
|
|
|
|
[Return to Testing documentation](index.md)
|