apiVersion: v1
kind: ConfigMap
metadata:
name: time-config
data:
TIME_FREQ: "6"
---
apiVersion: v1
kind: Pod
metadata:
name: time-check
spec:
containers:
- name: time-check
image: busybox:latest
command: ["/bin/sh"]
args: ["-c","while true; do date; sleep $TIME_FREQ;done >> /opt/data/time/time-check.log"]
env:
- name: TIME_FREQ
valueFrom:
configMapKeyRef:
name: time-config
key: TIME_FREQ
volumeMounts:
- name: log-volume
mountPath: /opt/data/time
volumes:
- name: log-volume
emptyDir: {}
According to documentation, to use variable you should put it in parentheses, however, that gives me:
TIME_FREQ: command not found
sleep: missing operand
If I use only $TIME_FREQ, the variable does not expand at all and sleep only complains about missing operand. I've tried curly braces, but didn't work, too.
If I set the variable locally, the config will accept it and the command runs ok, with variable defined as $TIME_FREQ.
Why does it not work?
Output from get:
apiVersion: v1
kind: Pod
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{},"name":"time-check","namespace":"default"},"spec":{"containers":[{"args":["-c","while true; do date; sleep ;done \u003e\u003e /opt/data/time/time-check.log"],"command":["/bin/sh"],"env":[{"name":"TIME_FREQ","valueFrom":{"configMapKeyRef":{"key":"TIME_FREQ","name":"time-config"}}}],"image":"busybox:latest","name":"time-check","volumeMounts":[{"mountPath":"/opt/data/time","name":"log-volume"}]}],"volumes":[{"emptyDir":{},"name":"log-volume"}]}}
creationTimestamp: "2024-09-01T12:07:41Z"
name: time-check
namespace: default
resourceVersion: "28228"
uid: 281e2819-df90-41c0-a5c4-b7203ed2ebec
spec:
containers:
- args:
- -c
- while true; do date; sleep ;done >> /opt/data/time/time-check.log
command:
- /bin/sh
env:
- name: TIME_FREQ
valueFrom:
configMapKeyRef:
key: TIME_FREQ
name: time-config
image: busybox:latest
imagePullPolicy: Always
name: time-check
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /opt/data/time
name: log-volume
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: kube-api-access-bm6wc
readOnly: true
dnsPolicy: ClusterFirst
enableServiceLinks: true
nodeName: minikube
preemptionPolicy: PreemptLowerPriority
priority: 0
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
serviceAccount: default
serviceAccountName: default
terminationGracePeriodSeconds: 30
tolerations:
- effect: NoExecute
key: node.kubernetes.io/not-ready
operator: Exists
tolerationSeconds: 300
- effect: NoExecute
key: node.kubernetes.io/unreachable
operator: Exists
tolerationSeconds: 300
volumes:
- emptyDir: {}
name: log-volume
- name: kube-api-access-bm6wc
projected:
defaultMode: 420
sources:
- serviceAccountToken:
expirationSeconds: 3607
path: token
- configMap:
items:
- key: ca.crt
path: ca.crt
name: kube-root-ca.crt
- downwardAPI:
items:
- fieldRef:
apiVersion: v1
fieldPath: metadata.namespace
path: namespace
status:
conditions:
- lastProbeTime: null
lastTransitionTime: "2024-09-01T12:07:49Z"
status: "True"
type: PodReadyToStartContainers
- lastProbeTime: null
lastTransitionTime: "2024-09-01T12:07:41Z"
status: "True"
type: Initialized
- lastProbeTime: null
lastTransitionTime: "2024-09-01T12:07:49Z"
status: "True"
type: Ready
- lastProbeTime: null
lastTransitionTime: "2024-09-01T12:07:49Z"
status: "True"
type: ContainersReady
- lastProbeTime: null
lastTransitionTime: "2024-09-01T12:07:41Z"
status: "True"
type: PodScheduled
containerStatuses:
- containerID: docker://abd378ce0519222c43fc194ba6952475176fba2bb37ee71a5ac9f6838239d2cb
image: busybox:latest
imageID: docker-pullable://busybox@sha256:82742949a3709938cbeb9cec79f5eaf3e48b255389f2dcedf2de29ef96fd841c
lastState: {}
name: time-check
ready: true
restartCount: 0
started: true
state:
running:
startedAt: "2024-09-01T12:07:49Z"
hostIP: 192.168.49.2
hostIPs:
- ip: 192.168.49.2
phase: Running
podIP: 10.244.0.6
podIPs:
- ip: 10.244.0.6
qosClass: BestEffort
startTime: "2024-09-01T12:07:41Z"
And describe:
Name: time-check
Namespace: default
Priority: 0
Service Account: default
Node: minikube/192.168.49.2
Start Time: Sun, 01 Sep 2024 14:07:41 +0200
Labels: <none>
Annotations: <none>
Status: Running
IP: 10.244.0.6
IPs:
IP: 10.244.0.6
Containers:
time-check:
Container ID: docker://abd378ce0519222c43fc194ba6952475176fba2bb37ee71a5ac9f6838239d2cb
Image: busybox:latest
Image ID: docker-pullable://busybox@sha256:82742949a3709938cbeb9cec79f5eaf3e48b255389f2dcedf2de29ef96fd841c
Port: <none>
Host Port: <none>
Command:
/bin/sh
Args:
-c
while true; do date; sleep ;done >> /opt/data/time/time-check.log
State: Running
Started: Sun, 01 Sep 2024 14:07:49 +0200
Ready: True
Restart Count: 0
Environment:
TIME_FREQ: <set to the key 'TIME_FREQ' of config map 'time-config'> Optional: false
Mounts:
/opt/data/time from log-volume (rw)
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-bm6wc (ro)
Conditions:
Type Status
PodReadyToStartContainers True
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
log-volume:
Type: EmptyDir (a temporary directory that shares a pod's lifetime)
Medium:
SizeLimit: <unset>
kube-api-access-bm6wc:
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 22m default-scheduler Successfully assigned default/time-check to minikube
Normal Pulling 22m kubelet Pulling image "busybox:latest"
Normal Pulled 22m kubelet Successfully pulled image "busybox:latest" in 7.077s (7.077s including waiting). Image size: 4261574 bytes.
Normal Created 22m kubelet Created container time-check
Normal Started 22m kubelet Started container time-check
