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版本:v1.8

容器注入

Sidecar 容器作为与业务容器解耦的存在,可以帮助我们很多辅助性的重要工作,比如常见的日志代理、用来实现 Service Mesh 等等。

注:这个运维特征默认在 VelaUX 处隐藏,你可以在 CLI 侧使用。

如何使用

这一次,让我们来编写一个应用部署计划里的组件 log-gen-worker。 同时我们将 sidecar 所记录的日志数据目录,和组件指向同一个数据存储卷 varlog。

cat <<EOF | vela up -f -
# YAML 文件开始
apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
name: vela-app-with-sidecar
spec:
components:
- name: log-gen-worker
type: worker
properties:
image: busybox
cmd:
- /bin/sh
- -c
- >
i=0;
while true;
do
echo "$i: $(date)" >> /var/log/date.log;
i=$((i+1));
sleep 1;
done
volumes:
- name: varlog
mountPath: /var/log
type: emptyDir
traits:
- type: sidecar
properties:
name: count-log
image: busybox
cmd: [ /bin/sh, -c, 'tail -n+1 -f /var/log/date.log']
volumes:
- name: varlog
path: /var/log
# YAML 文件结束
EOF

使用 vela ls 查看应用是否部署成功:

$ vela ls
APP COMPONENT TYPE TRAITS PHASE HEALTHY STATUS CREATED-TIME
vela-app-with-sidecar log-gen-worker worker sidecar running healthy 2021-08-29 22:07:07 +0800 CST

成功后,查看 Sidecar 所输出的日志

vela logs vela-app-with-sidecar --container count-log

从输出的日志可以看到读取日志的 sidecar 已经生效。

expected output
0: Fri Apr 16 11:08:45 UTC 2021
1: Fri Apr 16 11:08:46 UTC 2021
2: Fri Apr 16 11:08:47 UTC 2021
3: Fri Apr 16 11:08:48 UTC 2021
4: Fri Apr 16 11:08:49 UTC 2021
5: Fri Apr 16 11:08:50 UTC 2021
6: Fri Apr 16 11:08:51 UTC 2021
7: Fri Apr 16 11:08:52 UTC 2021
8: Fri Apr 16 11:08:53 UTC 2021
9: Fri Apr 16 11:08:54 UTC 2021