How Do I Set the umask Value for a Container?

Symptom

A container is started in tailf /dev/null mode and the directory permission is 700 after the startup script is manually executed. If the container is started by Kubernetes itself without tailf, the obtained directory permission is 751.

Solution

The reason is that the umask values set in the preceding two startup modes are different. Therefore, the permissions on the created directories are different.

The umask value is used to set the default permission for a newly created file or directory. If the umask value is too small, group users or other users will have excessive permissions, posing security threats to the system. Therefore, the default umask value for all users is set to 0077. That is, the default permission on directories created by users is 700, and the default permission on files is 600.

You can add the following content to the startup script to set the permission on the created directory to 700:

1. Add umask 0077 to the /etc/bashrc file and all files in /etc/profile.d/.
Run the following command:
```
echo "umask 0077" >> $FILE
```
FILE indicates the file name, for example, echo "umask 0077" >> /etc/bashrc.
Set the owner and group of the /etc/bashrc file and all files in /etc/profile.d/ to root.
Run the following command:
```
chown root.root $FILE
```