Manpages - subgid.5

subgid - the subordinate gid file

Each line in /etc/subgid contains a user name and a range of subordinate group ids that user is allowed to use. This is specified with three fields delimited by colons (“:”). These fields are:

·

login name or UID

·

numerical subordinate group ID

·

numerical subordinate group ID count

This file specifies the group IDs that ordinary users can use, with the newgidmap command, to configure gid mapping in a user namespace.

Multiple ranges may be specified per user.

When large number of entries (10000-100000 or more) are defined in /etc/subgid, parsing performance penalty will become noticeable. In this case it is recommended to use UIDs instead of login names. Benchmarks have shown speed-ups up to 20x.

/etc/subgid

Per user subordinate group IDs.

/etc/subgid-

Backup file for /etc/subgid.

*login.defs*(5), *newgidmap*(1), *newuidmap*(1), *newusers*(8), *subuid*(5), *useradd*(8), *userdel*(8), *usermod*(8), *user_namespaces*(7).