Linux – Adding user to chroot environment

chrootdebootstraplinuxUbuntu

I've created a chroot system in my Ubuntu using schroot and debrootstrap, based on minimal ubuntu. However whenever I can't seem to add a new user into this chroot environment. Here is what happens.

I enter schroot as root and add a new user.(Tried both adduser and useradd commands)
The username lists up in /etc/passwd file and I can 'su' into the new user. So far so good.
When I log out of schroot, and re-enter schroot, the user I created has vanished!! There is no mention of that user in /etc/passwd either.

How do I make the new user permanent?

Best Answer

Oh, I figured it out myself. Schroot has a feature called "sessions" where current environment can be preserved. Everytime one logs out without creating a "session", schroot brings everything to clean state and hence deletes the user as well. One can start a session using

schroot -c mychroot -b

Related Solutions

Linux commands “id” and “whoami” dependencies (for chroot environment)

Use ldd to check for linked libraries, e.g.:

 $ ldd $(which  whoami)
    linux-vdso.so.1 =>  (0x00007fff00bfe000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fa25f48e000)
    /lib64/ld-linux-x86-64.so.2 (0x00007fa25f871000)

Don't worry if you can't find linux-vdso on your system, see e.g.:

The library that you see as linux-vdso.so.1 is a virtual library or Virtual Dynamic Shared Object, that resides only in each program's address space. Older systems called this linux-gate.so.1. This virtual library provides the necessary logic to allow user programs to access system functions through the fastest means available on the particular processor, either interrupt, or with most newer processors, fast system call.

Linux – How to add a user to a group

The useradd command creates a new user or updates default new user information. It is not used to modify existing users. To add a user to another secondary group, you will need to user a command like the usermod command:

usermod -a -G profilers user1

As for why the gid is set to user1, this is because a default user's primary group is a group with the same name as the user. Each user has a single primary group and one to many secondary groups. Adding secondary groups will allow more access to folders, but changing the primary group has further reaching implications and should only be done for specific cases that require doing so.

To change a user's primary group, you can use this usermod command:

usermod -g profilers user1

Best Answer

Related Solutions

Linux commands “id” and “whoami” dependencies (for chroot environment)

Linux – How to add a user to a group

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