Environment
k8s集群 1.15版本
有网
docker ：18.06
Foreword
容器按照持续运行的时间可分为两类：服务类容器和工作类容器。
服务类容器通常持续提供服务，需要一直运行，比如 http server，daemon 等。工作类容器则是一次性任务，比如批处理程序，完成后容器就退出。
Kubernetes 的 Deployment、ReplicaSet 和 DaemonSet 都用于管理服务类容器；对于工作类容器，我们用 Job。
【单词】
completions n.完成( completion的名词复数 )结束（房地产等的）完成交易,完成交割
parallelism 美: [ˈpærəlɛlˌɪzəm]n.平行，对应，类似
job yaml templet
# cat echo.yaml
apiVersion: batch/v1
kind: Job
metadata:
name: myjob
spec:
completions: 6
parallelism: 2
template:
metadata:
name: myjob
spec:
containers:
- name: hello
image: busybox
command: ["echo", "hello CloudDeveloper"]
restartPolicy: OnFailure
# kubectl apply -f echo.yaml
The current pod status
2个pod并行运行，总共运行3轮，总共运行6次
# kubectl get pod -A
NAMESPACE NAME READY STATUS RESTARTS AGE
default myjob-2d9wl 0/1 Completed 0 20s
default myjob-6r2nr 0/1 ContainerCreating 0 1s
default myjob-fwhjd 0/1 Completed 0 13s
default myjob-lnf47 0/1 Completed 0 68s
default myjob-swljr 0/1 ContainerCreating 0 7s
default myjob-zvqdc 0/1 Completed 0 68s
kube-system coredns-5c98db65d4-stxrq 1/1 Running 1314 5d23h
kube-system coredns-5c98db65d4-vscdl 1/1 Running 1305 5d23h
kube-system etcd-adou 1/1 Running 2 5d23h
kube-system kube-apiserver-adou 1/1 Running 1172 5d23h
kube-system kube-controller-manager-adou 1/1 Running 4 5d23h
kube-system kube-flannel-ds-amd64-xqtf9 1/1 Running 2 5d23h
kube-system kube-proxy-8k2ch 1/1 Running 2 5d23h
kube-system kube-scheduler-adou 1/1 Running 4 5d23h
ns-monitor grafana-7bcb754f9d-wbmnh 1/1 Running 1 5d21h
ns-monitor node-exporter-k4c7j 1/1 Running 5 5d22h
ns-monitor prometheus-b54b8f85-t4brv 1/1 Running 6 5d22h
# kubectl get pod -A
NAMESPACE NAME READY STATUS RESTARTS AGE
default myjob-2d9wl 0/1 Completed 0 72s
default myjob-6r2nr 0/1 Completed 0 53s
default myjob-fwhjd 0/1 Completed 0 65s
default myjob-lnf47 0/1 Completed 0 2m
default myjob-swljr 0/1 Completed 0 59s
default myjob-zvqdc 0/1 Completed 0 2m
kube-system coredns-5c98db65d4-stxrq 1/1 Running 1314 5d23h
kube-system coredns-5c98db65d4-vscdl 1/1 Running 1305 5d23h
kube-system etcd-adou 1/1 Running 2 5d23h
kube-system kube-apiserver-adou 1/1 Running 1172 5d23h
kube-system kube-controller-manager-adou 1/1 Running 4 5d23h
kube-system kube-flannel-ds-amd64-xqtf9 1/1 Running 2 5d23h
kube-system kube-proxy-8k2ch 1/1 Running 2 5d23h
kube-system kube-scheduler-adou 1/1 Running 4 5d23h
ns-monitor grafana-7bcb754f9d-wbmnh 1/1 Running 1 5d21h
ns-monitor node-exporter-k4c7j 1/1 Running 5 5d22h
ns-monitor prometheus-b54b8f85-t4brv 1/1 Running 6 5d22h
The current docker status
运行完就自动退出，状态为Exited
# docker ps -a |grep hello
b3adfa19c76f busybox "echo 'hello CloudDe…" 2 minutes ago Exited (0) 2 minutes ago k8s_hello_myjob-6r2nr_default_29e2054c-0c34-4fd2-b22d-aacacd5c5bb9_0
38e6f4f9cd00 busybox "echo 'hello CloudDe…" 2 minutes ago Exited (0) 2 minutes ago k8s_hello_myjob-swljr_default_2b7367d9-ecf1-4a1a-bf7c-4b768a872ee5_0
491be5406d79 busybox "echo 'hello CloudDe…" 2 minutes ago Exited (0) 2 minutes ago k8s_hello_myjob-fwhjd_default_4e343d03-b598-435d-90ae-df2d99b4271f_0
1434bc5cd1e9 busybox "echo 'hello CloudDe…" 2 minutes ago Exited (0) 2 minutes ago k8s_hello_myjob-2d9wl_default_f32ec2c6-16d6-4fc1-b282-d8a560b2fc78_0
d25438091196 busybox "echo 'hello CloudDe…" 2 minutes ago Exited (0) 2 minutes ago k8s_hello_myjob-lnf47_default_6b704542-7796-4fc5-b507-cdd8b3edcbba_0
1c1cfe9938c4 busybox "echo 'hello CloudDe…" 2 minutes ago Exited (0) 2 minutes ago k8s_hello_myjob-zvqdc_default_bb1308f1-4b3d-432e-9c89-21eda9e9c797_0
The current job source of k8s
# kubectl get job -A -o wide
NAMESPACE NAME COMPLETIONS DURATION AGE CONTAINERS IMAGES SELECTOR
default myjob 6/6 79s 5m3s hello busybox controller-uid=c4db6b2d-810a-47bd-aa0e-445ea1fc58ed
Logs of job
# kubectl logs -f myjob-2d9wl
hello CloudDeveloper
对于 Job，只能设置为 Never 或者 OnFailure,失败不重启策略和失败重启策略
Clear job source
# kubectl delete -f echo.yaml
job.batch "myjob" deleted