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Infrastructure as code

Treating Haiku's infrastructure as cattle instead of kittens since 2017.

Directories

  • docs - Full documentation on Haiku's infrastructure
  • containers - Manifests to build and deploy containers
  • deployments - Kubernetes manifests for Haiku infrastructure
  • playground - Things that we're experimenting with. Not used in production.

Architecture

Architecture

Quickstart

These are the path of least resistance for new admins to do "things"

💥 DANGER
Never run kubectl delete on persistent volume claims you need! Running kubectl delete / kubectl delete -f on things describing volume claims will result in Kubernetes dropping (deleting) persistant volumes. (AKA massive + rapid data loss)

Running through the Kubernetes Basics class is recommended!

Pre-requirements

  • Install kubectl
  • Export the Kubernetes configuration from Digital Ocean, import locally
    • If this is your first kubernetes cluster, just put it at ~/.kube/config

Quick Commands

aka, i'm a sysadmin and a dog in a lab-coat

Check your configured cluster

List the known Kubernetes Clusters (contexts) of my client:

kubectl config get-contexts

Change the Kubernetes Cluster my local client focuses on:

kubectl config use-context (NAME)

List Deployments

Deployments are "how many desired sets of pods" within the cluster.

kubectl get deployments

Scaling Deployments

If you want something to "stop running for a while", this is the easiest and safest way. NEVER run kubectl delete if you don't know what you're doing.

kubectl scale --replicas=0 deployments/(NAME)

List Pods

Pods are one or more tightly related containers running in Kubernetes Deleting a Pod will result in the related deployment recreating it.

Entering a container

aka, equavient to docker exec -it (NAME) /bin/bash -l...

If the pod has one container:

kubectl exec -it pod/(NAME) -- /bin/bash -l

If the pod has multiple containers:

kubectl exec -it pod/(NAME) -c containername -- /bin/bash -l

Examining Stuff

kubectl describe pod/(NAME)
kubectl describe deployment/(NAME)

Initial Installation

  • Deploy ingress controller via instructions in deployments/ingress-controller/traefik
  • Deploy manifests in deployments for various services
  • Scale each deployment to 0 replicas
    • kubectl scale --replicas=0 deployments/(BLAH)
  • Populate persistent volumes for each application
    • see tools/migration_tools for some scripts to do this en-masse via rsync
  • Once ready for switchover, adjust DNS to new load balancer
  • Scale up applications
  • kubectl scale --replicas=1 deployments/(BLAH)

Rolling Restarts

To perform a rolling restart of each deployment replica:

kubectl rollout restart deployment/(NAME)

Example

-n kube-system is the namespace. We run Traefik in a seperate namespace since it's important.

Rolling restart of Traefik:

kubectl -n kube-system rollout restart daemonset/traefik-ingress-controller

Rolling Upgrade

Here we upgrade a container image from the command line. You can also update the matching yml document and run kubectl apply -f (thing).yml

Example

-n kube-system is the namespace. We run Traefik in a seperate namespace since it's important.

Rolling upgrade of Traefik:

kubectl -n kube-system set image daemonset/traefik-ingress-controller traefik-ingress-lb=docker.io/traefik:v2.6

Accessing Services / Pods

You can port-forward / tunnel from various points within the Kubernetes cluster to your local desktop. This is really useful for troubleshooting or understanding issues better.

Listen on localhost port 8888, to port 9999 within the pod

kubectl port-forward pod/(NAME) 8888:9999

Listen on localhost port 8080, to named port web of the service

kubectl port-forward service/(NAME) 8080:web

Pressing ctl+c will terminate the port-forwarding proxy

Importing data

Restoring volume / database backups: See deployments/other/restore.yml*

Manual database import: cat coolstuff.sql | kubectl exec -i deployment/postgres -- psql -U postgres

Forcing CronJobs

We leverage multiple jobs to perform various automatic activities within kubernetes. Some example jobs include postgresql backups to s3, persistent volume backups to s3, and syncing various git repositories.

Once and a while, you may want to force these jobs to run before performing maintenance, or for testing purposes.

  • pgbackup - PostgreSQL backup jobs
  • pvbackup - Persistent volume backup jobs

There are several example restore jobs in deployments/other. These can be manually edited and applied to restore data. It's highly recommended to review these CAREFULLY before use as a mistake could result in unattended data loss.

These restore jobs should be used on empty databases / persistent volumes only!

  1. Listing CronJobs 
    $ kubectl get cronjobs
NAME                        SCHEDULE      SUSPEND   ACTIVE   LAST SCHEDULE   AGE
discourse-pgbackup          0 0 * * 1,4   False     0        2d14h           6d13h
discourse-pvbackup          0 3 * * 3     False     0        11h             6d17h
gerrit-github-sync          0 * * * *     False     0        38m             13d
gerrit-pvbackup             0 1 * * 1,4   False     0        2d13h           8d
haikudepotserver-pgbackup   0 0 * * 1,4   False     0        2d14h           3d21h
.
  2. Forcing a CronJob to run This is a great thing to do before any maintenance :-) 
    $ kubectl create job --from=cronjob/discourse-pgbackup discourse-pgbackup-manual-220316
  3. Monitoring manual CronJob 
    $ kubectl get jobs
NAME                                 COMPLETIONS   DURATION   AGE
discourse-pgbackup-manual-220316     1/1           1m         1m

$ kubectl logs jobs/discourse-pgbackup-manual-220316
Backup discourse...
Backup complete!
Encryption complete!
Added `s3remote` successfully.
`/tmp/discourse_2022-03-14.sql.xz.gpg` -> `s3remote/haiku-backups/pg-discourse/discourse_2022-03-14.sql.xz.gpg`
Total: 0 B, Transferred: 136.45 MiB, Speed: 77.32 MiB/s
Snapshot of discourse completed successfully! (haiku-backups/pg-discourse/discourse_2022-03-14.sql.xz.gpg)

Secrets

For obvious reasons, 🔑 secrets are omitted from this repository.