Kubernetes配置映射符号链接(..data/):有什么方法可以避免它们? [英] Kubernetes config map symlinks (..data/) : is there a way to avoid them?

问题描述

我注意到，当我创建并挂载包含一些文本文件的配置映射时，容器会将这些文件视为指向../data/myfile.txt的符号链接.

I have noticed that when I create and mount a config map that contains some text files, the container will see those files as symlinks to ../data/myfile.txt .

例如，如果我的配置映射名为tc-configs并包含2个名为stripe1.xml和stripe2.xml的xml文件，如果我将此配置映射安装到容器中的/configs，则容器中将包含:

For example, if my config map is named tc-configs and contains 2 xml files named stripe1.xml and stripe2.xml, if I mount this config map to /configs in my container, I will have, in my container :

bash-4.4# ls -al /configs/
total 12
drwxrwxrwx    3 root     root          4096 Jun  4 14:47 .
drwxr-xr-x    1 root     root          4096 Jun  4 14:47 ..
drwxr-xr-x    2 root     root          4096 Jun  4 14:47 ..2018_06_04_14_47_03.291041453
lrwxrwxrwx    1 root     root            31 Jun  4 14:47 ..data -> ..2018_06_04_14_47_03.291041453
lrwxrwxrwx    1 root     root            18 Jun  4 14:47 stripe1.xml -> ..data/stripe1.xml
lrwxrwxrwx    1 root     root            18 Jun  4 14:47 stripe2.xml -> ..data/stripe2.xml

我猜Kubernetes需要这些符号链接以及../data和..timestamp/文件夹，但是我知道某些应用程序如果看到意外的文件或文件夹，则可能无法启动

I guess Kubernetes requires those symlinks and ../data and ..timestamp/ folders, but I know some applications that can fail to startup if they see non expected files or folders

有没有办法告诉Kubernetes不要生成所有这些符号链接并直接挂载文件?

Is there a way to tell Kubernetes not to generate all those symlinks and directly mount the files ?

推荐答案

我认为此解决方案令人满意:在mountPath中指定确切的文件路径，将摆脱指向..data and ..2018_06_04_19_31_41.860238952

I think this solution is satisfactory : specifying exact file path in mountPath, will get rid of the symlinks to ..data and ..2018_06_04_19_31_41.860238952

因此，如果我应用这样的清单:

So if I apply such a manifest :

apiVersion: v1
kind: Pod
metadata:
  name: my-lamp-site
spec:
    containers:
    - name: php
      image: php:7.0-apache
      volumeMounts:
      - mountPath: /var/www/html/users.xml
        name: site-data
        subPath: users.xml
    volumes:
    - name: site-data
      configMap:
        name: users

---

apiVersion: v1
kind: ConfigMap
metadata:
  name: users
data:
  users.xml: |
      <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
      <users>
      </users>

显然，我在显式地使用 subpath ，并且它们不是ConfigMaps的自动更新魔术"的一部分，我将不再看到任何符号链接:

Apparently, I'm making use of subpath explicitly, and they're not part of the "auto update magic" from ConfigMaps, I won't see any more symlinks :

$ kubectl exec  my-lamp-site -c php -- ls -al /var/www/html
total 12
drwxr-xr-x 1 www-data www-data 4096 Jun  4 19:18 .
drwxr-xr-x 1 root     root     4096 Jun  4 17:58 ..
-rw-r--r-- 1 root     root       73 Jun  4 19:18 users.xml

请注意不要忘记subPath，否则users.xml将是目录！

Be careful to not forget subPath, otherwise users.xml will be a directory !

回到我的初始清单:

spec:
    containers:
    - name: php
      image: php:7.0-apache
      volumeMounts:
      - mountPath: /var/www/html
        name: site-data
    volumes:
    - name: site-data
      configMap:
        name: users

我会看到这些符号链接回来:

I'll see those symlinks coming back :

$ kubectl exec  my-lamp-site -c php -- ls -al /var/www/html
total 12
drwxrwxrwx 3 root root 4096 Jun  4 19:31 .
drwxr-xr-x 3 root root 4096 Jun  4 17:58 ..
drwxr-xr-x 2 root root 4096 Jun  4 19:31 ..2018_06_04_19_31_41.860238952
lrwxrwxrwx 1 root root   31 Jun  4 19:31 ..data -> ..2018_06_04_19_31_41.860238952
lrwxrwxrwx 1 root root   16 Jun  4 19:31 users.xml -> ..data/users.xml

非常感谢 psycotica0 . "rel ="noreferrer"> K8s加拿大队的懈怠使我与子路径(在

Many thanks to psycotica0 on K8s Canada slack for putting me on the right track with subpath (they are quickly mentioned in configmap documentation)

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