1: 今天開始k8s 的的實踐啦:
示例:實現 運行在 Tomcat裏的 Web app,JSP頁面通過 JDBC 直接訪問 MySQL數據庫並展示數據。
需求:Web App 容器 MySQL容器,web--->mysql
需要把MySQL容器的IP地址通過環境變量的方式注入 Web App容器裏,同時,需要將Web App容器的 8080端口映射宿主機的 8080端口,以便在外部訪問。
1: 先編寫第一個yaml 文件;
1.YAML編寫
1.MySQL服務創建一個 RC 文件
# cat mysql-rc.yaml
apiVersion: apps/v1beta1 (把這行改成:apiVersion: extensions/v1beta1 就不報錯啦 )
kind: Deployment
metadata:
name: mysql
spec:
replicas: 1
selector:
matchLabels:
app: mysql
template:
metadata:
labels:
app: mysql
spec:
containers:
- name: mysql
image: mysql:5.7
ports:
- containerPort: 3306
env:
- name: MYSQL_ROOT_PASSWORD
value: "123456"
創建好以後:
[root@k8s-master script]# kubectl get pods
NAME READY STATUS RESTARTS AGE
mysql-4144028371-3v7nb 0/1 ContainerCreating 0 28s
然後trouble shooting :
kubectl describe pod
發現如下的報錯:
Error syncing pod, skipping: failed to "StartContainer" for "POD" with ErrImagePull: "image pull failed for registry.access.redhat.com/rhel7/pod-infrastructure:latest, this may be because there are no credentials on this request. details: (open /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt: no such file or directory)"
image 沒有pull:
下面一步步解決:
systemctl daemon-reload
service docker restart
service docker status (should see active (running))
[root@k8s-master script]# docker pull registry.access.redhat.com/rhel7/pod-infrastructure:latest
Trying to pull repository registry.access.redhat.com/rhel7/pod-infrastructure ...
open /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt: no such file or directory
發現還是少證書。
下面實踐瞭解決方法:
① wget http://mirror.centos.org/centos/7/os/x86_64/Packages/python-rhsm-certificates-1.19.10-1.el7_4.x86_64.rpm
② rpm2cpio python-rhsm-certificates-1.19.10-1.el7_4.x86_64.rpm | cpio -iv --to-stdout ./etc/rhsm/ca/redhat-uep.pem | tee /etc/rhsm/ca/redhat-uep.pem
前兩個命令會生成/etc/rhsm/ca/redhat-uep.pem文件.
③ docker pull registry.access.redhat.com/rhel7/pod-infrastructure:latest
成功了:
[root@k8s-master ca]# docker pull registry.access.redhat.com/rhel7/pod-infrastructure:latest
Trying to pull repository registry.access.redhat.com/rhel7/pod-infrastructure ...
latest: Pulling from registry.access.redhat.com/rhel7/pod-infrastructure
26e5ed6899db: Pull complete
66dbe984a319: Pull complete
9138e7863e08: Pull complete
Digest: sha256:92d43c37297da3ab187fc2b9e9ebfb243c1110d446c783ae1b989088495db931
Status: Downloaded newer image for registry.access.redhat.com/rhel7/pod-infrastructure:latest
-----
注意: 上面的操作在node 上都要再做一遍。
2: 下面把rc 刪除了重新建:
kubectl delete -f mysql-rc.yaml
kubectl create -f mysql-rc.yaml
3: 重起一下server, 或者 master,node 上的服務,就好了:
[root@k8s-master script]# kubectl get pod
NAME READY STATUS RESTARTS AGE
mysql-4144028371-l6d0m 1/1 Running 0 41m