mapping dns via argocd applicationset and external-dns

When using ArgoCD and an ApplicationSet to deploy external-dns to all clusters, as part of a grouping of addons common to all clusters, it can be useful to configure the DNS filter using variables:

          releaseName: "external-dns"
          - name: external-dns.domainFilters
            value: "{ {{name}} }"
          - name: external-dns.txtOwnerId
            value: '{{name}}'
          - name:
            value: '{{name}}'

This will place the cluster name as part of the dns name used by external-dns, resulting in the following type of FQDNs used by clusters:

Though, for my core cluster with components used by all clusters, I like to leave out the cluster name so all core components are at the k.<domain> level:

git-based homedir folder structure (and git repos) using lessons learned

After reinstalling everything including my main linux workbench system it became the right time to finally get my home directory into git.  Taking all lessons learned up till this point it seemed a good idea to cleanup my git repo strategy as well.  The revised strategy:

[Git repos]

- workbench-<user>

Team (i for infrastructure):
- i-ansible
- i-jenkins (needed ?)
- i-kubernetes (needed?)
- i-terraform
- i-tanzu

Project related: (source code)
- p-lido (use tagging dev/test/prod)

Jenkins project pipelines:
- j-lifecycle-cluster-decommission
- j-lifecycle-cluster-deploy
- j-lifecycle-cluster-update
- j-lido-dev
- j-lido-test
- j-lido-prod

Cluster app deployments:
- k-core
- k-dev
- k-exp
- k-prod

[Folder structure]

i-ansible (git repo)
  plays ( ~/a )

i-jenkins (git repo) (needed ?)
  pipelines ( ~/j )

i-kubernetes (git repo) (needed ?)
  manage ( ~/k )

i-terraform (git repo)
  plans (~/p)

i-tanzu (git repo)
  application.yaml (-> appofapps)
  apps (~/t)
    appofapps/ (inc all clusters)

  <gitrepo>/<user> (~/mysrc) (these are each git repos)
  <gitrepo>/<team> (~/s) (these are each git repos)
    - deploy cluster
    - create git repo
    - create adgroups
    - register with argocd global
      application.yaml (-> appofapps)
        appofapps/ (inc all apps)
      application.yaml (-> appofapps)
        appofapps/ (inc all apps)
      application.yaml (-> appofapps)
        appofapps/ (inc all apps)

workbench-<user> (git repo)

kubernetes disaster recovery

Deploying via git using argocd or flux makes disaster recovery fairly straightforward.

Using gitops means you can delete a kubernetes cluster, spin up a new one,  and have everything deployed back out in minutes.  But what about recovering the pvcs used before?

If you are using an infrastructure which implements csi, then you are able to allocate pvcs using storage managed outside of the cluster.  And, it turns out, reattaching to those pvcs is possible but you have to plan ahead.

Instead of writing yaml to spin up a pvc automatically, create the pv and pvc using manually set values.  Or spin up the pvcs automatically and then go back and modify the yaml to set recoverable values.  The howto is right up top in the csi documentation:

Similarly, it is common for applications to spin up with randomly set admin passwords and such.  However, imagine a recovery scenario where a new cluster is stood up, you don’t want a new password stood up.  Use a vault with a password and reference the vault.

These two steps do add a little work, it’s the idea of taking a little more time to do things right, and in a production environment you want this.

Infrastructure side solution:

Todo:  Create a video deleting a cluster and recovering all apps with a new cluster, recovering pvcs also (without any extra work on the recovery side).

fixing a wordpress pod after a brownout

Glad to have things back up though still looking into root cause, wouldn’t want to have to do this again.

Kubernetes utilities

So many utilities out there to explore:

Love how every k8s-at-home helm chart can pipe an application via a VPN sidecar through a few lines of yaml.  And, said sidecar can have its own VPN connection or use a single gateway pod with the VPN connection, so cool!

The bitnami team also has a great standard among their helm charts, for example, consistent ways to specify a local repo and ingresses.  Many works in progress.

Took at look at tor solutions just for fun, several proxies in kubernetes… as well as solutions ready to setup a server via an onion link using a tor kubernetes controller.  Think I’ll give it a try.

This kube rabbit hole is so much fun!

xcp-ng & kubernetes

Decided to test out xcp-ng as my underlying infrastructure to setup kubernetes clusters.

Initially xcp-ng, the open source implementation of Citrix’s XenServer, appears very similar to vmware yet the similarities disappear quickly.  VMware implemented the csi and cpi apis used by kubernetes integrations early on.  These implementations are only becoming more evolved whereas xcp-ng is looking for volunteers to begin the implementations.  Why start from scratch when vmware already has a developed solution?

What about a utility to spin up a cluster?  Google, AWS, and VMware all have a cli to spin up and work with clusters… xcp-ng not so much, would need to use a third party solution such as terraform.

xcp-ng is great on a budget but lacks the apis needed for a fully integrated kubernetes solution.  Clusters, and their storage solutions must be built and maintained manually.  At this point I wonder how anyone could choose a Citrix XenServer solution knowing everything is headed towards kubernetes.  But for a free solution with two or three manually managed clusters, yes.

and then we have argocd, with its ability to restore an entire cluster, even multiple clusters simultaneously simply due to its inherent declarative nature

more kubernetes magic


Like rebuilding a Shinto shrine

Traditionally Shinto shrines are rebuilt exactly the same next to the old shrine every so many years.  The old shrine is removed and when the time comes it will be rebuilt again.

Something similar can apply to home environments.  Recently I nuked everything and rebuilt from the ground up.  Something I’ve always done after 6 months or a year, for security reasons and to ensure I am always getting the fastest performance from infrastructure.

Such reinstalling is a natural fit for kubernetes.  There are several methods for spinning up a cluster, and after that just by the nature of kubernetes being yaml files it is easy to spin up the services you had running before, and watch them self register in the new dns and self generate certificates with the new active directory certificate authority.  Amazing.   Kubernetes is truly, a work of art.