Compress LDAP Transaction Log

[tretkowski]

There are some rare situations in which the LDAP Servers Transaction Log in Nubus is growing faster than expected and needs to be compressed.

0. ​The translog.mdb can be deleted from all LDAP primary and secondary pods, that are not primary-0.

1. Get a list of all LDAP primary and secondary pods:

kubectl -n ntretkowski-nubus get pods | grep -E 'nubus-ldap-server-(primary|secondary)'

2. For every LDAP primary and secondary that are not primary-0 delete the Transaction Log enter the pod:

kubectl -n ntretkowski-nubus exec nubus-ldap-server-primary-1 -c main -it -- /bin/bash

3. Delete the Transaction Log in the pod:

rm -f /var/lib/univention-ldap/translog/*

4. Restart LDAP primaries and secondaries:

kubectl -n ntretkowski-nubus delete pod nubus-ldap-server-primary-1
kubectl -n ntretkowski-nubus rollout restart statefulset/nubus-ldap-server-secondary

5. Save the amount of LDAP Primary Replicas to an environment variable:

LDAP_REPLICAS="`kubectl -n ntretkowski-nubus get statefulset nubus-ldap-server-primary -o jsonpath='replicas: {.spec.replicas}{"\n"}' | cut -d " " -f 2`"
echo ${LDAP_REPLICAS}

6. Scale down LDAP Primaries and LDAP Notifier to 0:

kubectl -n ntretkowski-nubus scale statefulset nubus-ldap-server-primary nubus-ldap-notifier --replicas=0

7. Create a ConfigMap and a Pod which does the work:

kubectl -n ntretkowski-nubus apply -f - <<EOF
apiVersion: v1
kind: ConfigMap
metadata:
  name: nubus-translog-debug
data:
  script.sh: |
    apt-get update
    apt-get install lmdb-utils
    cp -av /var/lib/univention-ldap/translog /temp-volume
    rm -f  /var/lib/univention-ldap/translog/*
    time mdb_copy -c /temp-volume/translog /var/lib/univention-ldap/translog
    chmod 600 /var/lib/univention-ldap/translog/data.mdb
    chown 101:102 /var/lib/univention-ldap/translog/data.mdb
    echo "----- before -----"
    ls -lh /temp-volume/translog/
    echo "------ after ------"
    ls -lh /var/lib/univention-ldap/translog/
    echo "Finished!"
    sleep infinity
---
apiVersion: v1
kind: Pod
metadata:
  name: nubus-translog-debug
spec:
  containers:
  - name: debug
    image: docker.software-univention.de/ucs-base-524:0.21.1
    command: ["/bin/bash", "/scripts/script.sh"]
    volumeMounts:
    - name: shared-data
      mountPath: /var/lib/univention-ldap
    - name: temp-volume
      mountPath: /temp-volume
    - name: scripts
      mountPath: /scripts
  volumes:
  - name: shared-data
    persistentVolumeClaim:
      claimName: shared-data-nubus-ldap-server-primary-0
  - name: temp-volume
    emptyDir: {}
  - name: scripts
    configMap:
      name: nubus-translog-debug
      defaultMode: 0755
EOF

7. Watch output of Debug Pod:

kubectl -n ntretkowski-nubus logs -f nubus-translog-debug

8. When it’s finished, delete Pod and ConfigMap:

kubectl -n ntretkowski-nubus delete pod nubus-translog-debug
kubectl -n ntretkowski-nubus delete configmap nubus-translog-debug

9. Rescale LDAP Notifier and Primaries:

kubectl -n ntretkowski-nubus scale statefulset nubus-ldap-notifier --replicas=1
kubectl -n ntretkowski-nubus scale statefulset nubus-ldap-server-primary --replicas=${LDAP_REPLICAS}