Talkyard on k8s
- Added notice about archiving talkyards-k8s repo as I am no longer using Talkyard (or for that matter any commenting solution). The content of this post might be outdated.
Talkyard is an open source software that provides discussion and commenting capabilities to sites.
For example the comments on this very site are powered by Talkyard.
As the official Talkyard releases already comes containerized and works well as a Docker Compose deployment I figured it would be a fun project to make Talkyard run on k8s. This post will be a step-by-step guide on how to deploy Talkyard to a Kubernetes cluster.
If you couldn’t care less about k8s there’s already instructions on how to install Talkyard with Docker Compose over at the official Talkyard git repository debiki/talkyard-prod-one. Talkyard is also available as Software as a Service if self-hosting is not an option, see talkyard.io/plans.
Table of contents
- Talkyard-k8s Repository
- Workspace Setup
- Talkyard Configuration
- Persistent Storage
- Update kustomization.yaml
- Deploy to Cluster
- Access Talkyard on localhost
- Configuring Ingress
I have setup a GitHub repository, ChrisEke/talkyard-k8s,
which I intend to keep up-to-date with new Talkyard releases.
Edit: Well, that did not really pan out. The repo has now been archived due to lack of maintenance from my part as I am no longer using Talkyard and unable to stay up to date with the latest features.
For those already familiar with k8s there are suggested quickstart instructions in the README. The remainder of this post will cover a deployment in more detail.
To follow along the following is needed:
a Kubernetes Cluster with amd64 worker node(s). Unfortunately the container images are not yet arm/arm64 compatible.
Kustomize (kubectl v1.14 and upwards includes Kustomize with the
--kustomize/-k-flag, but frozen to version v2.0.3. My recommendation is a stand alone installation of the latest version as there are a good deal of new features and improvements in later versions.)
This deployment is by default configured with minimal resource requirements. With all the different services combined 1.5GiB memory should be enough for a smaller community with limited concurrent updates.
The most memory intensive services are
search, which both are Java Runtime based applications. Pre-configured values for Java Heap size are
To modify these values the easiest approach is to update the environment variable, either as patch or with Kustomize ConfigMapGenerator.
configMapGenerator: - name: app-environment-vars behavior: merge namespace: talkyard literals: - PLAY_HEAP_MEMORY_MB="512" - name: search-environment-vars behavior: merge namespace: talkyard literals: - ES_JAVA_OPTS="-Xms384m -Xmx384m"
- Create workspace directory called
mkdir talkyard && cd talkyard
- Create the initial
kustomization.yamlfile which will reference GitHub repository ChrisEke/talkyard-k8s as source for all base manifests.
?ref=v0.2021.02-879ef3fe1 specifies which Talkyard version to deploy and can also be omitted completely to use the latest stable version.
cat << EOF > kustomization.yaml apiVersion: kustomize.config.k8s.io/v1beta1 kind: Kustomization namespace: talkyard resources: - github.com/ChrisEke/talkyard-k8s?ref=v0.2021.02-879ef3fe1 EOF
- Optionally we can now perform a dry-run to see the manifests of resources that will be deployed.
This will correspond to the manifests located in ChrisEke/talkyard-k8s/tree/v0.2021.02-879ef3fe1/manifests
kustomize build ./
Which should fill up the terminal with a lot of kubernetes manifest specifications, example:
--- apiVersion: apps/v1 kind: Deployment metadata: labels: app.kubernetes.io/component: webserver app.kubernetes.io/part-of: talkyard app.kubernetes.io/version: v0.2021.02-879ef3fe1 name: web namespace: talkyard
- Create the talkyard namespace in the cluster:
kubectl create namespace talkyard
Most of the application specific configuration is done in file
An up to date template can be found in repository debiki/talkyard-prod-one/blob/master/conf/play-framework.conf There’s also support for using ENV_VARS.
- Download latest
curl -SLO https://raw.githubusercontent.com/debiki/talkyard-prod-one/master/conf/play-framework.conf
- Configure Site Owner Email and optionally Outbound Email Server Settings in
... - talkyard.becomeOwnerEmailAddress="firstname.lastname@example.org" + talkyard.becomeOwnerEmailAddress="email@example.com" ...
Two secrets needs to be present for Talkyard to run:
play-secret-keyused by the application to sign session cookies (keep this safe and do not store in plaintext or checked into version control).
postgres-db-passwordfor database access.
- Generate random input for
head -c 32 /dev/urandom | base64 VqWhJDQ3EjZRKpU3eL+ctRGwgou2SQN3RUPz4+kNLsg=
- Store it as a Kubernetes Secret in talkyard namespace:
kubectl create secret -n talkyard generic talkyard-app-secrets \ --from-literal=play-secret-key='VqWhJDQ3EjZRKpU3eL+ctRGwgou2SQN3RUPz4+kNLsg='
- Set and create the database password:
kubectl create secret -n talkyard generic talkyard-rdb-secrets \ --from-literal=postgres-password='changeThis!'
Configuring and setting up persistent storage is optional while testing as the application will start up fine anyway. Note that if no persistent storage is configured all content and configuration made within Talkyard will be lost on pod restart. For production the following claims and volumes should be configured:
|component||volume name||mount path||access mode|
Example Database Storage
Here is an example for configuring the database storage. Attributes and parameters may differ depending on available storage classes in the cluster.
In this case I am using Longhorn to setup the persistent volume claim:
- Create a persistent volume claim:
cat << EOF > ./rdb-pvc.yaml apiVersion: v1 kind: PersistentVolumeClaim metadata: name: talkyard-rdb-pvc spec: accessModes: - ReadWriteOnce storageClassName: longhorn resources: requests: storage: 10Gi EOF
- Create a patch file for mounting the volume to rdb pod:
cat << EOF > ./patch-rdb-volume.yaml apiVersion: apps/v1 kind: Deployment metadata: name: patch-rdb-volume spec: strategy: type: Recreate template: spec: containers: - name: rdb env: - name: PGDATA value: /var/lib/postgresql/data/pgdata volumeMounts: - name: db-data mountPath: /var/lib/postgresql/data volumes: - name: db-data persistentVolumeClaim: claimName: talkyard-rdb-pvc EOF
Note that I’ve included strategy
Recreateto allow the volume to detach, e.g. during upgrade of the image version, and environment variable
PGDATAto use sub-folder pgdata to avoid postgres start-up error when data directory is not empty.
The directory structure of the workspace should now look like this:
talkyard/ ├── kustomization.yaml ├── patch-rdb-volume.yaml ├── play-framework.conf └── rdb-pvc.yaml
kustomization.yaml to include the configuration, PVC and patches:
apiVersion: kustomize.config.k8s.io/v1beta1 kind: Kustomization namespace: talkyard configMapGenerator: - name: app-play-framework-conf files: - app-prod-override.conf=play-framework.conf resources: - github.com/ChrisEke/talkyard-k8s?ref=v0.2021.02-879ef3fe1 - rdb-pvc.yaml patches: - path: patch-rdb-volume.yaml target: name: rdb kind: Deployment
I’m using the Kustomize built-in
configMapGeneratorto create a ConfigMap object of
play-framework.conf. This makes it easier to introduce changes to the configuration as the generated ConfigMap will have a hash value included in the name. Which guarantees that the pod will mount the most up to date configuration.
Deploy to Cluster
To trigger the deployment run:
kustomize build . | kubectl apply -f -
If everything went well
kubectl get pods -n talkyard should display the pods with status Running:
NAME READY STATUS RESTARTS AGE app-777b8d5689-pbwfp 1/1 Running 0 4m cache-5d6ddfd55-tg46c 1/1 Running 0 4m rdb-76d86b7c86-sh287 1/1 Running 0 4m search-66b6b6fc86-69tnh 1/1 Running 0 4m web-694745b5fd-wtwq8 1/1 Running 0 4m
Access Talkyard on localhost
By default the included nginx web server has strict configuration on what headers to allow and pass on to back-end services, which is good, as it decreases the attack surface for HTTP header injections.
But it also causes some trouble when port-forwarding
web service on an unprivileged port as the port number is stripped from the request URL-header for additional assets.
- A temporary workaround is to modify the nginx configuration in the
kubectl exec -n talkyard web-694745b5fd-wtwq8 -- \ sed -i 's/proxy_set_header Host \$host/proxy_set_header Host \$http_host/' \ /etc/nginx/server-locations.conf kubectl exec -n talkyard web-694745b5fd-wtwq8 -- nginx -s reload
- Now port-forward service
kubectl port-forward -n talkyard svc/web 8080:80
- Access http://localhost:8080/ in a browser and the Talkyard Welcome page should appear:
Proceed by signing up with the same email used earlier in
Continue with initial configuration of community name, creating topics and general layout etc.
When done remember to delete the
web pod to reset to default
kubectl delete -n talkyard pod web
Now we’re ready to expose Talkyard to the world via an Ingress object. In this example I’m using Traefik to automatically configure TLS certificate with Let’s Encrypt. Configuration of Traefik is beyond the scope of this post, but there are plenty of resources on the subject available online.
The IngressRoute will terminate HTTPS and then forward all traffic to
web service via HTTP on port 80.
- In file
play-framework.confchange the hostname to a proper domain name and enable HTTPS to ensure that generated URI:s from the application will use the correct protocol:
... - talkyard.hostname="localhost" + talkyard.hostname="talkyard-example.ekervhen.xyz" - talkyard.secure=false + talkyard.secure=true ...
- Create the IngressRoute manifest:
cat << "EOF" > ./ingressroute.yaml apiVersion: traefik.containo.us/v1alpha1 kind: IngressRoute metadata: name: talkyard-ingressroute spec: entryPoints: - websecure routes: - match: Host(`talkyard-example.ekervhen.xyz`) kind: Rule services: - name: web port: 80 tls: certResolver: letsencrypt EOF
ingressroute.yamlas a resource:
apiVersion: kustomize.config.k8s.io/v1beta1 kind: Kustomization namespace: talkyard configMapGenerator: - name: app-play-framework-conf files: - app-prod-override.conf=play-framework.conf resources: - github.com/ChrisEke/talkyard-k8s?ref=v0.2021.02-879ef3fe1 - rdb-pvc.yaml - ingressroute.yaml patches: - path: patch-rdb-volume.yaml target: name: rdb kind: Deployment
- Re-deploy with Kustomize and kubectl:
kustomize build . | kubectl apply -f -
With ingress and a valid certificate provisioned we should now be greeted by the Talkyard index page when accessing
With Talkyard successfully deployed the fun part of building a community can begin!
I want to highlight that there are most likely some additional tweaks and configuration required before this can be viewed as “production-ready”. Things like High Availability, Scalability and Backup Strategy are definitely worth looking into.
Questions? Suggestions? Errors spotted? Feel free to
comment with Talkyard below contact me!