Prepare for CSI snapshots with the snapshot validation webhook
Before we deploy snapshot-controller to actually manage the snapshots we take, we need the validation webhook to make sure it's done "right".
Snapshot Validation Webhook requirements
Snapshot Validation Webhook Namespace
We need a namespace to deploy our HelmRelease and associated YAMLs into. Per the flux design, I create this example yaml in my flux repo at
apiVersion: v1 kind: Namespace metadata: name: snapshot-validation-webhook
Snapshot Validation Webhook HelmRepository
We're going to install the Snapshot Validation Webhook helm chart from the piraeus-charts repository, so I create the following in my flux repo (assuming it doesn't already exist):
apiVersion: source.toolkit.fluxcd.io/v1beta1 kind: HelmRepository metadata: name: piraeus-charts namespace: flux-system spec: interval: 15m url: https://piraeus.io/helm-charts/
Snapshot Validation Webhook Kustomization
Now that the "global" elements of this deployment (just the HelmRepository in this case) have been defined, we do some "flux-ception", and go one layer deeper, adding another Kustomization, telling flux to deploy any YAMLs found in the repo at
/snapshot-validation-webhook/. I create this example Kustomization in my flux repo:
apiVersion: kustomize.toolkit.fluxcd.io/v1beta2 kind: Kustomization metadata: name: snapshot-validation-webhook namespace: flux-system spec: interval: 30m path: ./snapshot-validation-webhook prune: true # remove any elements later removed from the above path timeout: 10m # if not set, this defaults to interval duration, which is 1h sourceRef: kind: GitRepository name: flux-system healthChecks: - apiVersion: helm.toolkit.fluxcd.io/v2beta1 kind: HelmRelease name: snapshot-validation-webhook namespace: snapshot-validation-webhook
Fast-track your fluxing! 🚀
Is crafting all these YAMLs by hand too much of a PITA?
I automatically and instantly share (with my sponsors) a private "premix" git repository, which includes an ansible playbook to auto-create all the necessary files in your flux repository, for each chosen recipe!
Let the machines do the TOIL!
Snapshot Validation Webhook HelmRelease
Lastly, having set the scene above, we define the HelmRelease which will actually deploy snapshot-validation-webhook into the cluster. We start with a basic HelmRelease YAML, like this example:
apiVersion: helm.toolkit.fluxcd.io/v2beta1 kind: HelmRelease metadata: name: snapshot-validation-webhook namespace: snapshot-validation-webhook spec: chart: spec: chart: snapshot-validation-webhook version: 1.8.x # auto-update to semver bugfixes only (1) sourceRef: kind: HelmRepository name: piraeus-charts namespace: flux-system interval: 15m timeout: 5m releaseName: snapshot-validation-webhook values: # paste contents of upstream values.yaml below, indented 4 spaces (2)
- I like to set this to the semver minor version of the Snapshot Validation Webhook current helm chart, so that I'll inherit bug fixes but not any new features (since I'll need to manually update my values to accommodate new releases anyway)
- Paste the full contents of the upstream values.yaml here, indented 4 spaces under the
If we deploy this helmrelease as-is, we'll inherit every default from the upstream Snapshot Validation Webhook helm chart. That's probably hardly ever what we want to do, so my preference is to take the entire contents of the Snapshot Validation Webhook helm chart's values.yaml, and to paste these (indented), under the
values key. This means that I can then make my own changes in the context of the entire values.yaml, rather than cherry-picking just the items I want to change, to make future chart upgrades simpler.
Why not put values in a separate ConfigMap?
Didn't you previously advise to put helm chart values into a separate ConfigMap?
Yes, I did. And in practice, I've changed my mind.
Why? Because having the helm values directly in the HelmRelease offers the following advantages:
- If you use the YAML extension in VSCode, you'll see a full path to the YAML elements, which can make grokking complex charts easier.
- When flux detects a change to a value in a HelmRelease, this forces an immediate reconciliation of the HelmRelease, as opposed to the ConfigMap solution, which requires waiting on the next scheduled reconciliation.
- Renovate can parse HelmRelease YAMLs and create PRs when they contain docker image references which can be updated.
- In practice, adapting a HelmRelease to match upstream chart changes is no different to adapting a ConfigMap, and so there's no real benefit to splitting the chart values into a separate ConfigMap, IMO.
Then work your way through the values you pasted, and change any which are specific to your configuration.
Install Snapshot Validation Webhook!
Commit the changes to your flux repository, and either wait for the reconciliation interval, or force a reconcilliation using
flux reconcile source git flux-system. You should see the kustomization appear...
~ ❯ flux get kustomizations snapshot-validation-webhook NAME READY MESSAGE REVISION SUSPENDED snapshot-validation-webhook True Applied revision: main/70da637 main/70da637 False ~ ❯
The helmrelease should be reconciled...
~ ❯ flux get helmreleases -n snapshot-validation-webhook snapshot-validation-webhook NAME READY MESSAGE REVISION SUSPENDED snapshot-validation-webhook True Release reconciliation succeeded v1.8.x False ~ ❯
And you should have happy pods in the snapshot-validation-webhook namespace:
~ ❯ k get pods -n snapshot-validation-webhook -l app.kubernetes.io/name=snapshot-validation-webhook NAME READY STATUS RESTARTS AGE snapshot-validation-webhook-7c94b7446d-nwsss 1/1 Running 0 5m14s ~ ❯
What have we achieved? We now have the snapshot validation admission webhook running in the cluster, ready to support snapshot-controller!
- snapshot-validation-webhook running and ready to validate!
- Deploy snapshot-controller itself
Chef's notes 📓
///Footnotes Go Here///
Tip your waiter (sponsor) 👏
Did you receive excellent service? Want to compliment the chef? (..and support development of current and future recipes!) Sponsor me on Github / Ko-Fi / Patreon, or see the contribute page for more (free or paid) ways to say thank you! 👏
Employ your chef (engage) 🤝
Is this too much of a geeky PITA? Do you just want results, stat? I do this for a living - I'm a full-time Kubernetes contractor, providing consulting and engineering expertise to businesses needing short-term, short-notice support in the cloud-native space, including AWS/Azure/GKE, Kubernetes, CI/CD and automation.
Learn more about working with me here.
Flirt with waiter (subscribe) 💌
Want to know now when this recipe gets updated, or when future recipes are added? Subscribe to the RSS feed, or leave your email address below, and we'll keep you updated.