Redis pod failing - kubernetes

Question

I have redis DB setup running on my minikube cluster. I have shutdown my minikube and started after 3 days and I can see my redis pod is failing to come up with below error from pod log
Bad file format reading the append only file: make a backup of your AOF file, then use ./redis-check-aof --fix <filename>.
Below is my Stateful Set yaml file for redis master deployed via a helm chart
apiVersion: apps/v1
kind: StatefulSet
metadata:
annotations:
meta.helm.sh/release-name: test-redis
meta.helm.sh/release-namespace: test
generation: 1
labels:
app.kubernetes.io/component: master
app.kubernetes.io/instance: test-redis
app.kubernetes.io/managed-by: Helm
app.kubernetes.io/name: redis
helm.sh/chart: redis-14.8.11
name: test-redis-master
namespace: test
resourceVersion: "191902"
uid: 3a4e541f-154f-4c54-a379-63974d90089e
spec:
podManagementPolicy: OrderedReady
replicas: 1
revisionHistoryLimit: 10
selector:
matchLabels:
app.kubernetes.io/component: master
app.kubernetes.io/instance: test-redis
app.kubernetes.io/name: redis
serviceName: test-redis-headless
template:
metadata:
annotations:
checksum/configmap: dd1f90e0231e5f9ebd1f3f687d534d9ec53df571cba9c23274b749c01e5bc2bb
checksum/health: xxxxx
creationTimestamp: null
labels:
app.kubernetes.io/component: master
app.kubernetes.io/instance: test-redis
app.kubernetes.io/managed-by: Helm
app.kubernetes.io/name: redis
helm.sh/chart: redis-14.8.11
spec:
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- podAffinityTerm:
labelSelector:
matchLabels:
app.kubernetes.io/component: master
app.kubernetes.io/instance: test-redis
app.kubernetes.io/name: redis
namespaces:
- tyk
topologyKey: kubernetes.io/hostname
weight: 1
containers:
- args:
- -c
- /opt/bitnami/scripts/start-scripts/start-master.sh
command:
- /bin/bash
env:
- name: BITNAMI_DEBUG
value: "false"
- name: REDIS_REPLICATION_MODE
value: master
- name: ALLOW_EMPTY_PASSWORD
value: "no"
- name: REDIS_PASSWORD
valueFrom:
secretKeyRef:
key: redis-password
name: test-redis
- name: REDIS_TLS_ENABLED
value: "no"
- name: REDIS_PORT
value: "6379"
image: docker.io/bitnami/redis:6.2.5-debian-10-r11
imagePullPolicy: IfNotPresent
livenessProbe:
exec:
command:
- sh
- -c
- /health/ping_liveness_local.sh 5
failureThreshold: 5
initialDelaySeconds: 20
periodSeconds: 5
successThreshold: 1
timeoutSeconds: 6
name: redis
ports:
- containerPort: 6379
name: redis
protocol: TCP
readinessProbe:
exec:
command:
- sh
- -c
- /health/ping_readiness_local.sh 1
failureThreshold: 5
initialDelaySeconds: 20
periodSeconds: 5
successThreshold: 1
timeoutSeconds: 2
resources: {}
securityContext:
runAsUser: 1001
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /opt/bitnami/scripts/start-scripts
name: start-scripts
- mountPath: /health
name: health
- mountPath: /data
name: redis-data
- mountPath: /opt/bitnami/redis/mounted-etc
name: config
- mountPath: /opt/bitnami/redis/etc/
name: redis-tmp-conf
- mountPath: /tmp
name: tmp
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext:
fsGroup: 1001
serviceAccount: test-redis
serviceAccountName: test-redis
terminationGracePeriodSeconds: 30
volumes:
- configMap:
defaultMode: 493
name: test-redis-scripts
name: start-scripts
- configMap:
defaultMode: 493
name: test-redis-health
name: health
- configMap:
defaultMode: 420
name: test-redis-configuration
name: config
- emptyDir: {}
name: redis-tmp-conf
- emptyDir: {}
name: tmp
updateStrategy:
rollingUpdate:
partition: 0
type: RollingUpdate
volumeClaimTemplates:
- apiVersion: v1
kind: PersistentVolumeClaim
metadata:
creationTimestamp: null
labels:
app.kubernetes.io/component: master
app.kubernetes.io/instance: test-redis
app.kubernetes.io/name: redis
name: redis-data
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 8Gi
volumeMode: Filesystem
status:
phase: Pending
Please let me know your suggestions on how can I fix this.

Answer 1

I am not an Redis expert but from what I can see:
kubectl describe pod red3-redis-master-0
...
Bad file format reading the append only file: make a backup of your AOF file, then use ./redis-check-aof --fix <filename>
...
Means that your appendonly.aof file was corrupted with invalid byte sequences in the middle.
How we can proceed if redis-master is not working?:
Verify pvc attached to the redis-master-pod:
kubectl get pvc
NAME STATUS VOLUME
redis-data-red3-redis-master-0 Bound pvc-cf59a0b2-a3ee-4f7f-9f07-8f4922518359
Create new redis-client pod wit the same pvc redis-data-red3-redis-master-0:
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
name: redis-client
spec:
volumes:
- name: data
persistentVolumeClaim:
claimName: redis-data-red3-redis-master-0
containers:
- name: redis
image: docker.io/bitnami/redis:6.2.3-debian-10-r0
command: ["/bin/bash"]
args: ["-c", "sleep infinity"]
volumeMounts:
- mountPath: "/tmp"
name: data
EOF
Backup your files:
kubectl cp redis-client:/tmp .
Repair appendonly.aof file:
kubectl exec -it redis-client -- /bin/bash
cd /tmp
# make copy of appendonly.aof file:
cp appendonly.aof appendonly.aofbackup
# verify appendonly.aof file:
redis-check-aof appendonly.aof
...
0x 38: Expected prefix '*', got: '"'
AOF analyzed: size=62, ok_up_to=56, ok_up_to_line=13, diff=6
AOF is not valid. Use the --fix option to try fixing it.
...
# repair appendonly.aof file:
redis-check-aof --fix appendonly.aof
# compare files using diff:
diff appendonly.aof appendonly.aofbackup
Note:
As per docs:
The best thing to do is to run the redis-check-aof utility, initially without the --fix option, then understand the problem, jump at the given offset in the file, and see if it is possible to manually repair the file: the AOF uses the same format of the Redis protocol and is quite simple to fix manually. Otherwise it is possible to let the utility fix the file for us, but in that case all the AOF portion from the invalid part to the end of the file may be discarded, leading to a massive amount of data loss if the corruption happened to be in the initial part of the file.
In addition as described in the comments by #Miffa Young you can verify where your data is stored using k8s.io/minikube-hostpath provisioner:
kubectl get pv
...
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM
pvc-cf59a0b2-a3ee-4f7f-9f07-8f4922518359 8Gi RWO Delete Bound default/redis-data-red3-redis-master-0
...
kubectl describe pv pvc-cf59a0b2-a3ee-4f7f-9f07-8f4922518359
...
Source:
Type: HostPath (bare host directory volume)
Path: /tmp/hostpath-provisioner/default/redis-data-red3-redis-master-0
...
Your redis instance is failing down because your appendonly.aof is malformed and stored permanently under this location.
You can ssh into your vm:
minikube -p redis ssh
cd /tmp/hostpath-provisioner/default/redis-data-red3-redis-master-0
# from there you can backup/repair/remove your files:
Another solution is to install this chart using new name in this case new set of pv,pvc for redis StatefulSets will be created.

Answer 2

I think your redis is not quit Gracefully , so the AOF file is in a bad format What is AOF
you should repair aof file using a initcontainer by command (./redis-check-aof --fix .)
apiVersion: apps/v1
kind: StatefulSet
metadata:
annotations:
meta.helm.sh/release-name: test-redis
meta.helm.sh/release-namespace: test
generation: 1
labels:
app.kubernetes.io/component: master
app.kubernetes.io/instance: test-redis
app.kubernetes.io/managed-by: Helm
app.kubernetes.io/name: redis
helm.sh/chart: redis-14.8.11
name: test-redis-master
namespace: test
resourceVersion: "191902"
uid: 3a4e541f-154f-4c54-a379-63974d90089e
spec:
podManagementPolicy: OrderedReady
replicas: 1
revisionHistoryLimit: 10
selector:
matchLabels:
app.kubernetes.io/component: master
app.kubernetes.io/instance: test-redis
app.kubernetes.io/name: redis
serviceName: test-redis-headless
template:
metadata:
annotations:
checksum/configmap: dd1f90e0231e5f9ebd1f3f687d534d9ec53df571cba9c23274b749c01e5bc2bb
checksum/health: xxxxx
creationTimestamp: null
labels:
app.kubernetes.io/component: master
app.kubernetes.io/instance: test-redis
app.kubernetes.io/managed-by: Helm
app.kubernetes.io/name: redis
helm.sh/chart: redis-14.8.11
spec:
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- podAffinityTerm:
labelSelector:
matchLabels:
app.kubernetes.io/component: master
app.kubernetes.io/instance: test-redis
app.kubernetes.io/name: redis
namespaces:
- tyk
topologyKey: kubernetes.io/hostname
weight: 1
initContainers:
- name: repair-redis
image: docker.io/bitnami/redis:6.2.5-debian-10-r11
command: ['sh', '-c', "redis-check-aof --fix /data/appendonly.aof"]
containers:
- args:
- -c
- /opt/bitnami/scripts/start-scripts/start-master.sh
command:
- /bin/bash
env:
- name: BITNAMI_DEBUG
value: "false"
- name: REDIS_REPLICATION_MODE
value: master
- name: ALLOW_EMPTY_PASSWORD
value: "no"
- name: REDIS_PASSWORD
valueFrom:
secretKeyRef:
key: redis-password
name: test-redis
- name: REDIS_TLS_ENABLED
value: "no"
- name: REDIS_PORT
value: "6379"
image: docker.io/bitnami/redis:6.2.5-debian-10-r11
imagePullPolicy: IfNotPresent
livenessProbe:
exec:
command:
- sh
- -c
- /health/ping_liveness_local.sh 5
failureThreshold: 5
initialDelaySeconds: 20
periodSeconds: 5
successThreshold: 1
timeoutSeconds: 6
name: redis
ports:
- containerPort: 6379
name: redis
protocol: TCP
readinessProbe:
exec:
command:
- sh
- -c
- /health/ping_readiness_local.sh 1
failureThreshold: 5
initialDelaySeconds: 20
periodSeconds: 5
successThreshold: 1
timeoutSeconds: 2
resources: {}
securityContext:
runAsUser: 1001
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /opt/bitnami/scripts/start-scripts
name: start-scripts
- mountPath: /health
name: health
- mountPath: /data
name: redis-data
- mountPath: /opt/bitnami/redis/mounted-etc
name: config
- mountPath: /opt/bitnami/redis/etc/
name: redis-tmp-conf
- mountPath: /tmp
name: tmp
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext:
fsGroup: 1001
serviceAccount: test-redis
serviceAccountName: test-redis
terminationGracePeriodSeconds: 30
volumes:
- configMap:
defaultMode: 493
name: test-redis-scripts
name: start-scripts
- configMap:
defaultMode: 493
name: test-redis-health
name: health
- configMap:
defaultMode: 420
name: test-redis-configuration
name: config
- emptyDir: {}
name: redis-tmp-conf
- emptyDir: {}
name: tmp
updateStrategy:
rollingUpdate:
partition: 0
type: RollingUpdate
volumeClaimTemplates:
- apiVersion: v1
kind: PersistentVolumeClaim
metadata:
creationTimestamp: null
labels:
app.kubernetes.io/component: master
app.kubernetes.io/instance: test-redis
app.kubernetes.io/name: redis
name: redis-data
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 8Gi
volumeMode: Filesystem