SymptomsIt is not possible to log in to a container or a virtual machine via SSH nor via Parallels Power Panel (PPP). SSH silently quits, and PPP gives an error:
Invalid username or password, please try again.
Errors similar to those below can be observed in /var/log/messages:
Sep 26 12:30:53 suse sshd: Accepted keyboard-interactive/pam for root from 192.168.55.28 port 40406 ssh2
Sep 26 12:30:53 suse sshd: pam_loginuid(sshd:session): Cannot open /proc/self/loginuid: Read-only file system
Sep 26 12:30:53 suse sshd: pam_loginuid(sshd:session): set_loginuid failed
CauseMost likely, there is an instance of the "/proc" filesystem mounted as "read-only":
-bash-3.2# grep proc /etc/mtab
proc /proc proc ro,relatime 0 0
none /proc/sys/fs/binfmt_misc binfmt_misc rw,relatime 0 0
proc /var/named/run-root/proc proc ro,relatime 0 0
proc /tmp/myproc proc ro,relatime 0 0
There are known issues with CentOS and RedHat when mounting an instance of "/proc" as "read-only." For example, when BIND mounts "/var/named/run-root/proc" as "read-only," such an issue is caused.
ResolutionThe issue is not observed on 2.6.32 kernels, so the best way to eliminate the problem is to upgrade to Parallels Virtuozzo Containers for Linux 4.7.
There are two other ways to work around the issue:
1. Change BIND startup scripts so as not to mount the "/proc" filesystem as "read-only."
2. Disable "pam_loginuid.so" in the authentication rules:
~# sed '/pam_loginuid.so/s/^/#/g' -i /etc/pam.d/*
Additional InformationAlso see the following article:
6803 I cannot log in to the Parallels Power Panel – The message “Invalid username or password, please try again” appears.