(1) hostname
hostname环境变量保存了该Pod的hostname。
(2)容器和Pod的基本信息
Pod的名字、命名空间、IP以及容器的计算资源限制等可以以Downward API的方式获取并存储到环境变量中。基本上yaml里的信息都可以作为环境变量。
apiVersion: v1
kind: Pod
metadata:
name: test
spec:
containers:
- name: test-container
image: gcr.io/google_containers/busybox
resources:
requests:
memory: "32Mi"
cpu: "125m"
limits:
memory: "64Mi"
cpu: "250m"
env:
- name: MY_NODE_NAME
valueFrom:
fieldRef:
fieldPath: spec.nodeName
- name: MY_POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: MY_POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
- name: MY_POD_IP
valueFrom:
fieldRef:
fieldPath:
status.podIP
- name: MY_POD_SERVICE_ACCOUNT
valueFrom:
fieldRef:
fieldPath:
spec.serviceAccountName
- name: MY_CPU_REQUEST
valueFrom:
resourceFieldRef:
containerName: test-container resource: requests.cpu
(3) 集群中服务的信息
容器的环境变量中还包括了容器运行前创建的所有服务的信息，比如默认的kubernetes服务对应了环境变量
KUBERNETES_PORT_443_TCP_ADDR=10.0.0.1
KUBERNETES_SERVICE_HOST=10.0.0.1
KUBERNETES_SERVICE_PORT=443
KUBERNETES_SERVICE_PORT_HTTPS=443
KUBERNETES_PORT=tcp://10.0.0.1:443
KUBERNETES_PORT_443_TCP=tcp://10.0.0.1:443
KUBERNETES_PORT_443_TCP_PROTO=tcp
KUBERNETES_PORT_443_TCP_PORT=443