Using system users for a given site

[NotionCommotion]

I created a specific Linux user responsible to host a given site, created a postgresql user and database with the same name, and created a pool, and all is good...  Almost.

How can I make the user a system user (i.e. useradd -r my_user) without a home?  Without a home, where should ssh keys go?  Anything need to be changed when creating the postgresql user?

Thanks

[gw1500se]

SSH keys go in the home directory by default. You can change that in /etc/ssh/sshd_config by modifying the AuthorizedKeysFile directive to point where ever you want.

Edited July 24, 2021 by gw1500se

[NotionCommotion]

Thanks gw1500se,

/etc/ssh/sshd_config has AuthorizedKeysFile set to the typical .ssh/authorized_keys.  But isn't this relative to the user's home?  And I thought that system users typically didn't have a home.  I didn't realize until now that when I create a new system user with the -r flag, /etc/passwd still shows it as having a home (i.e. my_user:x:983:979::/home/my_user:/bin/bash) even though there is no /home/my_user directory.  Now that I am thinking about it, seems like if I want the user to be able to use ssh keys, I will need to create a home for it and the only decision is whether I want to locate it in /home or somewhere else and I might as well located in /home (agree?).  

I was first thinking there might have been something special regarding the postgresql user because I was getting the following, however, I have since discovered that the user was still created and I get the same warning for even user's which do have a home.  I don't remember having this happen in the past but seems like a non-issue.

$ sudo -u postgres createuser my_user
could not change directory to "/home/michael": Permission denied

 

man useradd

       -r, --system
           Create a system account.

           System users will be created with no aging information in /etc/shadow, and their numeric identifiers are chosen in the SYS_UID_MIN-SYS_UID_MAX range, defined in /etc/login.defs, instead of UID_MIN-UID_MAX (and their GID
           counterparts for the creation of groups).

           Note that useradd will not create a home directory for such a user, regardless of the default setting in /etc/login.defs (CREATE_HOME). You have to specify the -m options if you want a home directory for a system account
           to be created.