1   TL;DR¶

Summit EFD deployment on k3s managed by Argo CD.

If you need help, please drop a line on the #com-square-support LSSTC Slack channel.

2   Why are we doing this?¶

The EFD system is based on Kafka and InfluxDB to record telemetry, commands, and events for the Rubin Observatory. It was prototyped and tested with the simulator for the M1M3 subsystem. The next logical step is to deploy and test it with real hardware at the Summit.

The ability to deploy the EFD at different environments quickly and reproduce these deployments is crucial. To solve this problem we’ve adopted Kubernetes as our deployment platform, Helm as the Kubernetes package manager and Argo CD as the continuous delivery tool for Kubernetes.

In this technote, we demonstrate that we can deploy the EFD on a single machine with Docker and k3s while the final on-premise production cluster is not ready to receive the EFD.

3   Provisioning a k3s cluster¶

The first step is to provision our Kubernetes cluster. k3s is a lightweight Kubernetes that runs in a container, and k3d is a helper tool to install k3s.

sudo systemctl enable docker

curl -s https://raw.githubusercontent.com/rancher/k3d/main/install.sh | bash

export HOST_PATH=/data
export CONTAINER_PATH=/var/lib/rancher/k3s/storage/

sudo /usr/local/bin/k3d cluster create efd  --network host --no-lb --volume ${HOST_PATH}:${CONTAINER_PATH} --k3s-arg "--disable=traefik"

sudo /usr/local/bin/k3d kubeconfig get efd > k3s.yaml
export KUBECONFIG=$(pwd)/k3s.yaml

kubectl cluster-info

Kubernetes control plane is running at https://0.0.0.0:6443
CoreDNS is running at https://0.0.0.0:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
Metrics-server is running at https://0.0.0.0:6443/api/v1/namespaces/kube-system/services/https:metrics-server:/proxy

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'

4   Install Argo CD¶

With Argo CD we keep the EFD deployment configuration on GitHub. This way we can use GitHub to control changes in the EFD deployments and easily bootstrap new EFD deployments.

kubectl create namespace argocd
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

This creates a new namespace, argocd, where Argo CD services and application resources will live.

Follow these instructions to install Argo CD CLI.

Additional Argo CD configuration includes Single Sign On (SSO) and the Role Based Access Control (RBAC).

In particular, this is the RBAC configuration we added to the ArgoCD ConfigMap argocd-rbac-cm to let members of the EFD ops team in the lsst-sqre GitHub organization to synchronize the EFD configuration, while granting read-only permission for other members.

data:
  policy.csv: |
    p, lsst-sqre:EFD ops, applications, sync, default/*, allow

    g, lsst-sqre:EFD ops, role:admin
  policy.default: role:readonly

5   Deploy the EFD¶

Once Argo CD is installed we can deploy the EFD.

Argo CD manages the deployment of the EFD on multiple environments.

For example, the following bootstraps an EFD deployment using the configuration for the summit environment:

kubectl port-forward svc/argocd-server -n argocd 8080:443

kubectl -n argocd get secret argocd-initial-admin-secret -o jsonpath="{.data.password}" | base64 -d

argocd login --insecure localhost:8080
argocd app create efd --dest-namespace argocd --dest-server https://kubernetes.default.svc --repo https://github.com/lsst-sqre/argocd-efd.git --path apps/efd --helm-set env=summit

argocd app sync efd

See the Argo CD getting started guide for further instructions on how to login using the CLI.

The secrets used by the EFD are stored on LSST’s Vault Service but you need to create at least one secret manually with the Vault read token for this environment.

Sync the vault-secrets-operator app:

argocd app sync vault-secrets-operator

export VAULT_TOKEN=<vault token>
export VAULT_TOKEN_LEASE_DURATION=8640

kubectl create secret generic vault-secrets-operator --from-literal=VAULT_TOKEN=$VAULT_TOKEN --from-literal=VAULT_TOKEN_LEASE_DURATION=$VAULT_TOKEN_LEASE_DURATION --namespace vault-secrets-operator

Sync the ingress-nginx app:

argocd app sync ingress-nginx

Finally sync the other apps either using Argo CD CLI or the GUI.

Create the tls-certs secret for Argo CD:

cat << EOF | kubectl apply -f -
apiVersion: ricoberger.de/v1alpha1
kind: VaultSecret
metadata:
  name: argocd-server-tls
  namespace: argocd
spec:
  path: secret/k8s_operator/summit-lsp.lsst.codes/efd/tls-certs
  type: Opaque
EOF

Service names follow the convention <app>-<environment>-efd.lsst.codes, for example, chronograf-summit-efd.lsst.codes

Change reclaim policy of new volumes to retain

kubectl patch pv <new pv> -p '{"spec":{"persistentVolumeReclaimPolicy":"Retain"}}'

For Kafka, the broker URL for the Summit EFD is kafka-0-summit-efd.lsst.codes:31090.

6   Testing the EFD¶

The EFD deployment can be tested using kafkacat a command line utility implemented with librdkafka the Apache Kafka C/C++ client library.

Run in producer mode (-P) to produce messages for a test topic:

kafkacat -P -b <kafka broker url> -t test_topic
Hello EFD!
^D

Run in metadata listing mode (-L) to retrieve metadata from the cluster:

kafkacat -L -b <kafka broker url>

The -d option enables librdkafka debugging. For instance, -d broker can be used to debug connection issues with the cluster:

kafkacat -L -b <kafka broker url>  -d broker

Run in consumer mode (-C) to consume topics from the cluster:

kafkacat -C -b <kafka broker url> -t <topic name>

7   Restarting the EFD manually¶

k3d ensures k3s automatically starts after a system reboot. In case you need to start the k3s container manually, first check its status:

sudo docker ps -a

If the k3s container status is Exited, start it with the following command:

sudo docker start <k3s container name>

After a few minutes, all Kubernetes pods should be running again:

export KUBECONFIG=$(pwd)/k3s.yaml
kubectl cluster-info
kubectl get pods --all-namespaces

8   Inspecting logs, restarting pods, etc.¶

You can inspect logs, restart pods and do other operations including synchronization of the deployment using the Argo CD UI or the CLI.

In the case of the EFD, we have most often needed to restart the kafka connector pod confluent-cp-kafka-connect in the cp-helm-charts namespace.

9   Accessing EFD data¶

Use the Chronograf UI for data visualization and dashboarding.

In this notebook we show how to access EFD data using the EFD Python client, and proceed with data analysis using Pandas dataframes.