Apache server runs with docker run but kubernetes pod fails with CrashLoopBackOff - docker

Question

My application uses apache2 web server. Due to restrictions in the kubernetes cluster, I do not have root previliges inside pod. So I have changed default port of apache2 from 80 to 8080 to be able to run as non-root user.
My problem is that once I build the docker image and run it in local it runs fine, but when I deploy using kubernetes in the cluster it keeps failing with:
Action '-D FOREGROUND' failed.
resulting in CrashLoopBackOff.
So, basically the apache2 server is not able to run in the pod with non-root user, but runs fine in local with docker run.
Any help is appreciated.
I am attaching my deployment and service files for reference:
apiVersion: apps/v1
kind: Deployment
metadata:
name: &DeploymentName app
spec:
replicas: 1
selector:
matchLabels: &appName
app: *DeploymentName
template:
metadata:
name: main
labels:
<<: *appName
spec:
securityContext:
fsGroup: 2000
runAsUser: 1000
runAsGroup: 3000
volumes:
- name: var-lock
emptyDir: {}
containers:
- name: *DeploymentName
image: image:id
ports:
- containerPort: 8080
volumeMounts:
- mountPath: /etc/apache2/conf-available
name: var-lock
- mountPath: /var/lock/apache2
name: var-lock
- mountPath: /var/log/apache2
name: var-lock
- mountPath: /mnt/log/apache2
name: var-lock
readinessProbe:
tcpSocket:
port: 8080
initialDelaySeconds: 180
periodSeconds: 60
livenessProbe:
tcpSocket:
port: 8080
initialDelaySeconds: 300
periodSeconds: 180
imagePullPolicy: Always
tty: true
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
envFrom:
- configMapRef:
name: *DeploymentName
resources:
limits:
cpu: 1
memory: 2Gi
requests:
cpu: 1
memory: 2Gi
---
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
name: &hpaName app
spec:
maxReplicas: 1
minReplicas: 1
scaleTargetRef:
apiVersion: extensions/v1beta1
kind: Deployment
name: *hpaName
targetCPUUtilizationPercentage: 60
---
apiVersion: v1
kind: Service
metadata:
labels:
app: app
name: app
spec:
selector:
app: app
ports:
- protocol: TCP
name: http-web-port
port: 80
targetPort: 8080
- protocol: TCP
name: https-web-port
port: 443
targetPort: 443

Answer 1

CrashLoopBackOff is a common error in Kubernetes, indicating a pod constantly crashing in an endless loop.
The CrashLoopBackOff error can be caused by a variety of issues, including:
Insufficient resources-lack of resources prevents the container from loading Locked file—a file was already locked by another container
Locked database-the database is being used and locked by other pods
Failed reference—reference to scripts or binaries that are not present on the container
Setup error- an issue with the init-container setup in Kubernetes
Config loading error—a server cannot load the configuration file.
Misconfigurations- a general file system misconfiguration
Connection issues—DNS or kube-DNS is not able to connect to a third-party service
Deploying failed services—an attempt to deploy services/applications that have already failed (e.g. due to a lack of access to other services)
To fix kubernetes CrashLoopbackoff error refer to this link and also check out stackpost for more information.