I am trying to create multiple containers in a single pod. I am facing following issue:
YAML file:
apiVersion: v1
kind: Pod
metadata:
name: multi-containers
spec:
restartPolicy: Never
volumes:
- name: multi-data
emptyDir: {}
containers:
- name: nginx-multicontainerone
image: nginx
volumeMounts:
- name: multi-data
mountPath: /one
- name: nginx-multicontainertwo
image: nginx
volumeMounts:
- name: multi-data
mountPath: /two
- name: debian-container
image: debian
volumeMounts:
- name: multi-data
mountPath: /pod-data
command: ["/bin/sh"]
args: ["-c", "echo Hello from the debian container > /pod-data/index.html"]
Below is the output of describe command:
Kubectl describe pod multi-containers
Name: multi-containers
Namespace: default
Priority: 0
Node: docker-desktop/192.168.65.4
Start Time: Mon, 01 Nov 2021 20:07:08 0530
Labels: <none>
Annotations: <none>
Status: Running
IP: 10.1.0.238
IPs:
IP: 10.1.0.238
Containers:
nginx-multicontainerone:
Container ID: docker://91561db271c29670880de55dda6a5f1724de42583d5712807f37dbc1597aa2ea
Image: nginx
Image ID: docker-pullable://nginx@sha256:644a70516a26004c97d0d85c7fe1d0c3a67ea8ab7ddf4aff193d9f301670cf36
Port: <none>
Host Port: <none>
State: Running
Started: Mon, 01 Nov 2021 20:07:28 0530
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/one from multi-data (rw)
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-n6hst (ro)
nginx-multicontainertwo:
Container ID: docker://049e08584f49e7970fac5b1fbb60dbf67c9928944123336c62ec423a7c656239
Image: nginx
Image ID: docker-pullable://nginx@sha256:644a70516a26004c97d0d85c7fe1d0c3a67ea8ab7ddf4aff193d9f301670cf36
Port: <none>
Host Port: <none>
State: Terminated
Reason: Error
Exit Code: 1
Started: Mon, 01 Nov 2021 20:07:32 0530
Finished: Mon, 01 Nov 2021 20:07:34 0530
Ready: False
Restart Count: 0
Environment: <none>
Mounts:
/two from multi-data (rw)
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-n6hst (ro)
debian-container:
Container ID: docker://8eb1b494e3da1672cef86bbe34af11f3e6f2e148ab56fbb969aca1f81205d5fa
Image: debian
Image ID: docker-pullable://debian@sha256:4d6ab716de467aad58e91b1b720f0badd7478847ec7a18f66027d0f8a329a43c
Port: <none>
Host Port: <none>
Command:
/bin/sh
Args:
-c
echo Hello from the debian container > /pod-data/index.html
State: Terminated
Reason: Completed
Exit Code: 0
Started: Mon, 01 Nov 2021 20:07:35 0530
Finished: Mon, 01 Nov 2021 20:07:35 0530
Ready: False
Restart Count: 0
Environment: <none>
Mounts:
/pod-data from multi-data (rw)
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-n6hst (ro)
Conditions:
Type Status
Initialized True
Ready False
ContainersReady False
PodScheduled True
Volumes:
multi-data:
Type: EmptyDir (a temporary directory that shares a pod's lifetime)
Medium:
SizeLimit: <unset>
kube-api-access-n6hst:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 66s default-scheduler Successfully assigned default/multi-containers to docker-desktop
Normal Pulling 65s kubelet Pulling image "nginx"
Normal Pulled 47s kubelet Successfully pulled image "nginx" in 18.2903658s
Normal Created 47s kubelet Created container nginx-multicontainerone
Normal Started 47s kubelet Started container nginx-multicontainerone
Normal Pulling 47s kubelet Pulling image "nginx"
Normal Pulled 44s kubelet Successfully pulled image "nginx" in 3.285316s
Normal Created 43s kubelet Created container nginx-multicontainertwo
Normal Started 43s kubelet Started container nginx-multicontainertwo
Normal Pulling 43s kubelet Pulling image "debian"
Normal Pulled 40s kubelet Successfully pulled image "debian" in 3.3076706s
Normal Created 40s kubelet Created container debian-container
Normal Started 40s kubelet Started container debian-container
Command: kubectl get pods Result: multi-containers 1/3
NotReady 0 14m
Main Goal of this exercise: I am using shared emptyDir volume and trying to access index.html in the containers "nginx-multicontainerone", "nginx-multicontainertwo"
CodePudding user response：
I ran your pod on Minikube and I was able to reproduce the issue. Because all containers in a pod share the same network interface, the first container acquires the default port (80) for Nginx in your pod. Subsequently, the other Nginx container fails when it attempts binding to the same port. To check the logs of the failing container, you can use the following command.
kubectl logs multi-containers nginx-multicontainertwo
When I ran it, I got the following output.
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2021/11/01 15:02:10 [emerg] 1#1: bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/11/01 15:02:10 [emerg] 1#1: bind() to [::]:80 failed (98: Address already in use)
nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
2021/11/01 15:02:10 [notice] 1#1: try again to bind() after 500ms
2021/11/01 15:02:10 [emerg] 1#1: bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/11/01 15:02:10 [emerg] 1#1: bind() to [::]:80 failed (98: Address already in use)
nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
2021/11/01 15:02:10 [notice] 1#1: try again to bind() after 500ms
2021/11/01 15:02:10 [emerg] 1#1: bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/11/01 15:02:10 [emerg] 1#1: bind() to [::]:80 failed (98: Address already in use)
nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
2021/11/01 15:02:10 [notice] 1#1: try again to bind() after 500ms
2021/11/01 15:02:10 [emerg] 1#1: bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/11/01 15:02:10 [emerg] 1#1: bind() to [::]:80 failed (98: Address already in use)
nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
2021/11/01 15:02:10 [notice] 1#1: try again to bind() after 500ms
2021/11/01 15:02:10 [emerg] 1#1: bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
2021/11/01 15:02:10 [emerg] 1#1: bind() to [::]:80 failed (98: Address already in use)
nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
2021/11/01 15:02:10 [notice] 1#1: try again to bind() after 500ms
2021/11/01 15:02:10 [emerg] 1#1: still could not bind()
nginx: [emerg] still could not bind()
Try assigning different port configurations to each Nginx instance.