VPS – Issues

SSH Issues

1) Unable to open pty: No such file or directory

From the NOD

vzctl exec VEID /sbin/MAKEDEV /dev/pty
vzctl exec VEID /sbin/MAKEDEV /dev/tty
vzctl enter VEID

To Fix this issue permanently,

1. Edit the file /etc/rc.sysinit of the VPS server

2. Comment the line

3. Add the following lines after /sbin/start_udev:

/sbin/MAKEDEV tty
/sbin/MAKEDEV pty

4. Reboot your VPS
vzctl restart VEID


2) awk string came when we login to the vps

Get into the VPS and edit the file .bash_profile

vi .bash_profile
Comment the line include the awk strings


3) sshd dead but subsys locked

sshd -d
rm /dev/null
mknod /dev/null c 1 3
/etc/init.d/sshd restart


4) Unable to fork: Cannot allocate memory


While logging to a VPS from the host server(main node) , you see the message:

Unable to fork: Cannot allocate memory

This usually occurs when VPS is running out of resources especially RAM. Restarting the vps may be a temporary fix which allows you to enter the server . But it prevents executing some commands throwing the same error message .

You can increase privvmpages and kmemsize values for the VPS in order to solve the issue .From the client node in order to see each resource , run the command

cat /proc/user_beancounters

It has five values associated with it: current usage, maximum usage , barrier, limit, and fail counter. The meaning of barrier and limit is parameter-dependent; in short, those can be thought of as a soft limit and a hard limit. If any resource hits the limit, the fail counter for it is increased. This allows the owner to detect problems by monitoring /proc/user_beancounters in the container.

uid      resource         held        maxheld    barrier          limit failcnt

101:    kmemsize       5741113  8347532   2147483646  2147483646 453225323642

privvmpages    33656     44989       98304          98304 106507

In order to increase the value of the two parameters edit the below file from the main node

/etc/sysconfig/vz-scripts/101.conf ( 101 is my vps node)

You can see the value as below


Increase the value as you need


Restart your vps after the changes .

# vzctl restart 101

You can also raise the limit as sown below from the host node .

vzctl set 101 –privvmpages 100000:100000 –save

vzctl restart 101


Size of unswappable memory in bytes, allocated by the operating system kernel.


Memory allocation limit. Privvmpages parameter allows controlling the amount of memory allocated by applications.

Tags: logicsupport review, server management, technical support, Unable to fork: Cannot allocate memory, VPS

This entry was posted on Monday, November 30th, 2009 at 8:36 am and is filed under VPS. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.


Container already locked



rm -rf /vz/lock/<VID>.lck
vzctl chkpnt <VID> –kil


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