Add a storage node

Steps to add a storage node to an OpenShift 4 cluster on Exoscale.

Starting situation

You already have a OpenShift 4 cluster on Exoscale
You have admin-level access to the cluster
You want to add a new storage node to the cluster

Prerequisites

The following CLI utilities need to be available locally:

docker
curl
kubectl
oc
exo >= v1.28.0 Exoscale CLI
vault Vault CLI
commodore, see Running Commodore
jq
yq yq YAML processor (version 4 or higher)
macOS: gdate from GNU coreutils, brew install coreutils

Prepare local environment

Create local directory to work in

We strongly recommend creating an empty directory, unless you already have a work directory for the cluster you’re about to work on. This guide will run Commodore in the directory created in this step.

export WORK_DIR=/path/to/work/dir
mkdir -p "${WORK_DIR}"
pushd "${WORK_DIR}"

Configure API access

Access to cloud API

export EXOSCALE_API_KEY=<exoscale-key> (1)
export EXOSCALE_API_SECRET=<exoscale-secret>
export EXOSCALE_ZONE=<exoscale-zone> (2)
export EXOSCALE_S3_ENDPOINT="sos-${EXOSCALE_ZONE}.exo.io"

1	We recommend setting up an IAMv3 role called `unrestricted` with "Default Service Strategy" set to `allow` if it doesn’t exist yet.
2	All lower case. For example `ch-dk-2`.

Access to VSHN GitLab

# From https://git.vshn.net/-/profile/personal_access_tokens, "api" scope is sufficient
export GITLAB_TOKEN=<gitlab-api-token>
export GITLAB_USER=<gitlab-user-name>

Access to VSHN Lieutenant

# For example: https://api.syn.vshn.net
# IMPORTANT: do NOT add a trailing `/`. Commands below will fail.
export COMMODORE_API_URL=<lieutenant-api-endpoint>

# Set Project Syn cluster and tenant ID
export CLUSTER_ID=<lieutenant-cluster-id> # Looks like: c-<something>
export TENANT_ID=$(curl -sH "Authorization: Bearer $(commodore fetch-token)" ${COMMODORE_API_URL}/clusters/${CLUSTER_ID} | jq -r .tenant)

Configuration for hieradata commits

export GIT_AUTHOR_NAME=$(git config --global user.name)
export GIT_AUTHOR_EMAIL=$(git config --global user.email)
export TF_VAR_control_vshn_net_token=<control-vshn-net-token> # use your personal SERVERS API token from https://control.vshn.net/tokens

Get required tokens from Vault

Connect with Vault

export VAULT_ADDR=https://vault-prod.syn.vshn.net
vault login -method=oidc

Grab the LB hieradata repo token from Vault

export HIERADATA_REPO_SECRET=$(vault kv get \
  -format=json "clusters/kv/lbaas/hieradata_repo_token" | jq '.data.data')
export HIERADATA_REPO_USER=$(echo "${HIERADATA_REPO_SECRET}" | jq -r '.user')
export HIERADATA_REPO_TOKEN=$(echo "${HIERADATA_REPO_SECRET}" | jq -r '.token')

Compile the catalog for the cluster. Having the catalog available locally enables us to run Terraform for the cluster to make any required changes.
```
commodore catalog compile "${CLUSTER_ID}"
```

Set alert silence

Set a silence in Alertmanager for all rook-ceph alerts

if [[ "$OSTYPE" == "darwin"* ]]; then alias date=gdate; fi
job_name=$(printf "POST-silence-rook-ceph-alerts-$(date +%s)" | tr '[:upper:]' '[:lower:]')
silence_duration='+60 minutes' (1)
kubectl --as=cluster-admin -n openshift-monitoring create -f- <<EOJ
apiVersion: batch/v1
kind: Job
metadata:
  name: ${job_name}
  labels:
    app: silence-rook-ceph-alerts
spec:
 backoffLimit: 0
 template:
  spec:
    restartPolicy: Never
    containers:
      - name: silence
        image: quay.io/appuio/oc:v4.13
        command:
        - bash
        - -c
        - |
          curl_opts=( --cacert /etc/ssl/certs/serving-certs/service-ca.crt --header "Content-Type: application/json" --header "Authorization: Bearer \$(cat /var/run/secrets/kubernetes.io/serviceaccount/token)" --resolve alertmanager-main.openshift-monitoring.svc.cluster.local:9095:\$(getent hosts alertmanager-operated.openshift-monitoring.svc.cluster.local | awk '{print \$1}' | head -n 1) --silent )
          read -d "" body << EOF
          {
            "matchers": [
              {
                "name": "syn_component",
                "value": "rook-ceph",
                "isRegex": false
              }
            ],
            "startsAt": "$(date -u +'%Y-%m-%dT%H:%M:%S')",
            "endsAt": "$(date -u +'%Y-%m-%dT%H:%M:%S' --date "${silence_duration}")",
            "createdBy": "$(kubectl config current-context | cut -d/ -f3)",
            "comment": "Silence rook-ceph alerts"
          }
          EOF

          curl "\${curl_opts[@]}" \
            "https://alertmanager-main.openshift-monitoring.svc.cluster.local:9095/api/v2/silences" \
            -XPOST -d "\${body}"

        volumeMounts:
        - mountPath: /etc/ssl/certs/serving-certs/
          name: ca-bundle
          readOnly: true
        - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
          name: kube-api-access
          readOnly: true
    serviceAccountName: prometheus-k8s
    volumes:
    - name: ca-bundle
      configMap:
        defaultMode: 288
        name: serving-certs-ca-bundle
    - name: kube-api-access
      projected:
        defaultMode: 420
        sources:
          - serviceAccountToken:
              expirationSeconds: 3607
              path: 'token'
EOJ

1	Adjust this variable to create a longer or shorter silence

Extract Alertmanager silence ID from job logs

silence_id=$(kubectl --as=cluster-admin -n openshift-monitoring logs jobs/${job_name} | \
  jq -r '.silenceID')

Update Cluster Config

Update cluster config.

pushd "inventory/classes/${TENANT_ID}/"

yq eval -i ".parameters.openshift4_terraform.terraform_variables.storage_count =
  (.parameters.openshift4_terraform.terraform_variables.storage_count // 3) + 1" \
  ${CLUSTER_ID}.yml

yq eval -i ".parameters.rook_ceph.ceph_cluster.node_count =
  (.parameters.rook_ceph.ceph_cluster.node_count // 3) + 1" \
  ${CLUSTER_ID}.yml

Review and commit

# Have a look at the file ${CLUSTER_ID}.yml.

git commit -a -m "Add storage node to cluster ${CLUSTER_ID}"
git push

popd

Compile and push cluster catalog

commodore catalog compile ${CLUSTER_ID} --push -i

Prepare Terraform environment

Configure Terraform secrets

cat <<EOF > ./terraform.env
EXOSCALE_API_KEY
EXOSCALE_API_SECRET
TF_VAR_control_vshn_net_token
GIT_AUTHOR_NAME
GIT_AUTHOR_EMAIL
HIERADATA_REPO_TOKEN
EOF

Setup Terraform

Prepare Terraform execution environment

# Set terraform image and tag to be used
tf_image=$(\
  yq eval ".parameters.openshift4_terraform.images.terraform.image" \
  dependencies/openshift4-terraform/class/defaults.yml)
tf_tag=$(\
  yq eval ".parameters.openshift4_terraform.images.terraform.tag" \
  dependencies/openshift4-terraform/class/defaults.yml)

# Generate the terraform alias
base_dir=$(pwd)
alias terraform='docker run -it --rm \
  -e REAL_UID=$(id -u) \
  --env-file ${base_dir}/terraform.env \
  -w /tf \
  -v $(pwd):/tf \
  --ulimit memlock=-1 \
  "${tf_image}:${tf_tag}" /tf/terraform.sh'

export GITLAB_REPOSITORY_URL=$(curl -sH "Authorization: Bearer $(commodore fetch-token)" ${COMMODORE_API_URL}/clusters/${CLUSTER_ID} | jq -r '.gitRepo.url' | sed 's|ssh://||; s|/|:|')
export GITLAB_REPOSITORY_NAME=${GITLAB_REPOSITORY_URL##*/}
export GITLAB_CATALOG_PROJECT_ID=$(curl -sH "Authorization: Bearer ${GITLAB_TOKEN}" "https://git.vshn.net/api/v4/projects?simple=true&search=${GITLAB_REPOSITORY_NAME/.git}" | jq -r ".[] | select(.ssh_url_to_repo == \"${GITLAB_REPOSITORY_URL}\") | .id")
export GITLAB_STATE_URL="https://git.vshn.net/api/v4/projects/${GITLAB_CATALOG_PROJECT_ID}/terraform/state/cluster"

pushd catalog/manifests/openshift4-terraform/

Initialize Terraform

terraform init \
  "-backend-config=address=${GITLAB_STATE_URL}" \
  "-backend-config=lock_address=${GITLAB_STATE_URL}/lock" \
  "-backend-config=unlock_address=${GITLAB_STATE_URL}/lock" \
  "-backend-config=username=${GITLAB_USER}" \
  "-backend-config=password=${GITLAB_TOKEN}" \
  "-backend-config=lock_method=POST" \
  "-backend-config=unlock_method=DELETE" \
  "-backend-config=retry_wait_min=5"

Add node

Run Terraform to spin up a new node
```
terraform apply
```

Approve node cert for new storage node

# Once CSRs in state Pending show up, approve them
# Needs to be run twice, two CSRs for each node need to be approved

kubectl --as=cluster-admin get csr -w

oc --as=cluster-admin get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | \
  xargs oc --as=cluster-admin adm certificate approve

kubectl --as=cluster-admin get nodes

Label and taint the new storage node

kubectl get node -ojson | \
  jq -r '.items[] | select(.metadata.name | test("storage-")).metadata.name' | \
  xargs -I {} kubectl --as=cluster-admin label node {} node-role.kubernetes.io/storage=

kubectl --as=cluster-admin taint node -lnode-role.kubernetes.io/storage \
  storagenode=True:NoSchedule

Wait until the new OSD is launched. This requires ArgoCD to have run and the Rook-Ceph operator to notice the change. This might take a few minutes.
```
kubectl --as=cluster-admin -n syn-rook-ceph-cluster get pods -w
```

Wait for the data to be redistributed ("backfilled") to the new OSD.

When backfilling is completed, ceph status should show all PGs as active+clean.

Depending on the number of OSDs in the storage cluster and the amount of data that needs to be moved, this may take a while.

If the storage cluster is mostly idle, you can speed up backfilling by temporarily setting the following configuration.

kubectl --as=cluster-admin -n syn-rook-ceph-cluster exec -it deploy/rook-ceph-tools -- \
  ceph config set osd osd_mclock_override_recovery_settings true (1)
kubectl --as=cluster-admin -n syn-rook-ceph-cluster exec -it deploy/rook-ceph-tools -- \
  ceph config set osd osd_max_backfills 10 (2)

1	Allow overwriting `osd_max_backfills`.
2	The number of PGs which are allowed to backfill in parallel. Adjust up or down depending on client load on the storage cluster.

After backfilling is completed, you can remove the configuration with

kubectl --as=cluster-admin -n syn-rook-ceph-cluster exec -it deploy/rook-ceph-tools -- \
  ceph config rm osd osd_max_backfills
kubectl --as=cluster-admin -n syn-rook-ceph-cluster exec -it deploy/rook-ceph-tools -- \
  ceph config rm osd osd_mclock_override_recovery_settings

kubectl --as=cluster-admin -n syn-rook-ceph-cluster exec -it deploy/rook-ceph-tools -- \
  ceph status

Finish up

Remove silence in Alertmanager

if [[ "$OSTYPE" == "darwin"* ]]; then alias date=gdate; fi
job_name=$(printf "DELETE-silence-rook-ceph-alerts-$(date +%s)" | tr '[:upper:]' '[:lower:]')
kubectl --as=cluster-admin -n openshift-monitoring create -f- <<EOJ
apiVersion: batch/v1
kind: Job
metadata:
  name: ${job_name}
  labels:
    app: silence-rook-ceph-alerts
spec:
 backoffLimit: 0
 template:
  spec:
    restartPolicy: Never
    containers:
      - name: silence
        image: quay.io/appuio/oc:v4.13
        command:
        - bash
        - -c
        - |
          curl_opts=( --cacert /etc/ssl/certs/serving-certs/service-ca.crt --header "Content-Type: application/json" --header "Authorization: Bearer \$(cat /var/run/secrets/kubernetes.io/serviceaccount/token)" --resolve alertmanager-main.openshift-monitoring.svc.cluster.local:9095:\$(getent hosts alertmanager-operated.openshift-monitoring.svc.cluster.local | awk '{print \$1}' | head -n 1) --silent )

          curl "\${curl_opts[@]}" \
            "https://alertmanager-main.openshift-monitoring.svc.cluster.local:9095/api/v2/silence/${silence_id}" \
            -XDELETE

        volumeMounts:
        - mountPath: /etc/ssl/certs/serving-certs/
          name: ca-bundle
          readOnly: true
        - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
          name: kube-api-access
          readOnly: true
    serviceAccountName: prometheus-k8s
    volumes:
    - name: ca-bundle
      configMap:
        defaultMode: 288
        name: serving-certs-ca-bundle
    - name: kube-api-access
      projected:
        defaultMode: 420
        sources:
          - serviceAccountToken:
              expirationSeconds: 3607
              path: 'token'
EOJ

Clean up Alertmanager silence jobs

kubectl --as=cluster-admin -n openshift-monitoring delete jobs -l app=silence-rook-ceph-alerts