Docker Registry定期清理方式
作者：mofei12138
Docker Registry因镜像堆积需定期清理,可通过配置文件开启删除、调用API、执行garbage-collect命令或Python脚本保留最新版本,并设置crontab定时任务自动化处理
背景
项目在持续部署过程中会push镜像到Registry中，随着时间推移，Registry中会保存大量镜像，造成磁盘空间不足，所以需要定期清理历史镜像，保证Registry服务正常运行。
删除镜像流程
- Registry默认是不允许删除镜像的，需要修改/etc/docker/registry/config.yml配置文件来开启删除操作，如下：
version: 0.1
log:
fields:
service: registry
storage:
delete:
enabled: true #打开delete开关
cache:
blobdescriptor: inmemory
filesystem:
rootdirectory: /var/lib/registry
http:
addr: :5000
headers:
X-Content-Type-Options: [nosniff]
health:
storagedriver:
enabled: true
interval: 10s
threshold: 3
- 调用Registry API删除镜像
# 查询digest curl -I -H "Accept: application/vnd.docker.distribution.manifest.v2+json" localhost:5000/v2/nginx/manifests/latest # 根据digest删除镜像 curl -i -X DELETE localhost:5000/v2/nginx/manifests/sha256:89a42c3ba15f09a3fbe39856bddacdf9e94cd03df7403cad4fc105088e268fc9
- 在Registry容器中执行garbage-collect命令删除未被引用的layer
registry garbage-collect /etc/docker/registry/config.yml
- 重启registry容器（不重启的话，会导致刚清理的同名同tag镜像无法push）
使用Python脚本清理镜像（保留每个镜像的最新版本）
import os
import requests
class RegistryHandler(object):
get_repos_url = '/v2/_catalog'
get_tags_url = '/v2/{repo}/tags/list'
get_digests_url = '/v2/{repo}/manifests/{tag}'
delete_digest_url = '/v2/{repo}/manifests/{digest}'
def __init__(self, host):
self.host = host
def get_repos(self):
url = f'{self.host}{self.get_repos_url}'
res = requests.get(url).json()
return res['repositories']
def get_tags(self, repo):
url = f'{self.host}{self.get_tags_url.format(repo=repo)}'
res = requests.get(url).json()
return res['tags']
def get_digest(self, repo, tag):
headers = {"Accept": "application/vnd.docker.distribution.manifest.v2+json"}
url = f'{self.host}{self.get_digests_url.format(repo=repo, tag=tag)}'
resp = requests.get(url, headers=headers)
return resp.headers['Docker-Content-Digest']
def delete_digest(self, repo, digest):
url = f'{self.host}{self.delete_digest_url.format(repo=repo, digest=digest)}'
requests.delete(url)
if __name__ == '__main__':
rh = RegistryHandler('http://localhost:5000')
repos = rh.get_repos()
for repo in repos:
tags = rh.get_tags(repo)
if not tags:
continue
delete_tags = sorted(
filter(lambda tag: '.' in tag, tags),
key=lambda tag: ''.join([f'{int(n):04d}' for n in tag.split('.')])
)[:-1]
for tag in delete_tags:
try:
digest = rh.get_digest(repo, tag)
rh.delete_digest(repo, digest)
except Exception as e:
print(f'{repo}:{tag} delete fail: {e}')
os.system("docker exec `docker ps | grep registry | awk '{print $1}'` registry garbage-collect --delete-untagged /etc/docker/registry/config.yml")
os.system("docker restart `docker ps | grep registry | awk '{print $1}'`")
配置定期清理
crontab配置如下：
0 0 * * * /usr/bin/python ~/registry_clear.py
参考：
- https://docs.docker.com/registry/spec/api/#deleting-an-image
- https://docs.docker.com/registry/garbage-collection/
总结
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。