我的服务需要一个 cfg 文件,在容器运行之前需要更改。因此,将 cfg 打包到 Docker 镜像中是不合适的。
我需要从集群复制到容器中,然后在容器中启动服务并读取该 cfg。
我该怎么做?
我该怎么做?
我认为对于你的用例,初始化容器可能是最适合的选择。 初始化容器就像是在kubernetes pod中启动自己的容器之前可以运行的小型脚本,它们必须退出。您可以在初始化容器和容器之间的共享持久卷中更新此配置文件。
以下文章提供了一个很好的示例,说明如何完成这个过程:
更新:
我在stackoverflow上找到了另一个答案,可能与此相关并能给出更好的解决方案:
can i use a configmap created from an init container in the pod
一个例子
输出
NAME READY STATUS RESTARTS AGE
cassandra-0 1/1 Running 0 70s
[root@green--1 ~]# k exec -it cassandra-0 -n green -- /bin/bash
root@cassandra-0:/# ls /config/cassandra/
cassandra.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: cassandra
namespace: green
labels:
app: cassandra
spec:
serviceName: cassandra
replicas: 1
selector:
matchLabels:
app: cassandra
template:
metadata:
labels:
app: cassandra
spec:
terminationGracePeriodSeconds: 1800
initContainers:
- name: copy
image: busybox:1.28
command: ["/bin/sh", "-c", "cp /config/cassandra.yaml /config/cassandra/"]
volumeMounts:
- name: tmp-config
mountPath: /config/cassandra/
- name: cassandraconfig
mountPath: /config/
containers:
- name: cassandra
#image: gcr.io/google-samples/cassandra:v13
image: cassandra:3.11.6
imagePullPolicy: Always
#command: [ "/bin/sh","-c","su cassandra && mkdir -p /etc/cassandra/ && cp /config/cassandra/cassandra.yaml /etc/cassandra/" ]
ports:
- containerPort: 7000
name: intra-node
- containerPort: 7001
name: tls-intra-node
- containerPort: 7199
name: jmx
- containerPort: 9042
name: cql
resources:
limits:
cpu: "500m"
memory: 4Gi
requests:
cpu: "500m"
memory: 4Gi
securityContext:
capabilities:
add:
- IPC_LOCK
lifecycle:
postStart:
exec:
command:
- /bin/sh
- -c
- "cp /config/cassandra/cassandra.yaml /etc/cassandra/"
preStop:
exec:
command:
- /bin/sh
- -c
- nodetool drain
env:
- name: MAX_HEAP_SIZE
value: 1G
- name: HEAP_NEWSIZE
value: 100M
- name: CASSANDRA_SEEDS
value: "cassandra-0.cassandra.green.svc.cluster.local"
- name: CASSANDRA_CLUSTER_NAME
value: "green"
- name: CASSANDRA_DC
value: "ee1-green"
- name: CASSANDRA_RACK
value: "Rack1-green"
- name: POD_IP
valueFrom:
fieldRef:
fieldPath: status.podIP
readinessProbe:
exec:
command:
- /bin/bash
- -c
- /ready-probe.sh
initialDelaySeconds: 15
timeoutSeconds: 55
volumeMounts:
- name: cassandradata
mountPath: /cassandra_data
- name: tmp-config
mountPath: /config/cassandra/
volumes:
- name: cassandraconfig
configMap:
name: cassandraconfig
- name: tmp-config
emptyDir: {}
# 1 Creating a volume to move date from init container to main container without making mount ReadOnly
# These are converted to volume claims by the controller
# and mounted at the paths mentioned above.
volumeClaimTemplates:
- metadata:
name: cassandradata
spec:
accessModes: [ "ReadWriteOnce" ]
storageClassName: rook-ceph-block
resources:
requests:
storage: 5Gi