Proxmox web interface became unavailable and was not listening on port 8006. Also unable to backup a running KVM. This all pointed towards a missing/corrupt package.

To fix, the following was carried out:

1. Update repositories

nano /etc/apt/sources.list

Insert the relevant sources from here: http://pve.proxmox.com/wiki/Package_repositories#Proxmox_VE_No-Subscription_Repository – In this case it was the no subscription for Proxmox VE 4.x repositories.

Now run the following commands:

apt-get update
apt-get install pve-manager

Pve-manager seemed to be corrupt. Updating to the latest version fixed the issue.

qm start vmid

Source: http://pve.proxmox.com/wiki/Manual:_qm

I had to do this for an older version of Proxmox as web interface was broken.

Edit cron for proxmox:

vim /etc/cron.d/vzdump

e.g. Output:

[html]
# cluster wide vzdump cron schedule
# Atomatically generated file – do not edit

PATH=”/usr/sbin:/usr/bin:/sbin:/bin”

0 1 * * 1,4,6 root vzdump 101 103 104 105 –quiet 1 –mode snapshot –mailto hello@email.com –compress gzip –storage backupdrive

vzdump --dumpdir /mnt/backups/ --compress gzip 120

Breakdown:

• –dumpdir – location backup is going to be placed
• –compress gzip – specify compression type (gzip, lzo)
• 120 – container ID

Proxmox container was failing to backup and from the log files the following errors appeared over and over:

• Cannot stat: Input/output error
• Cannot stat: No such file or directory

From carrying out quite a bit of research implementing the following seems to solve the issue:

Edit /etc/vzdump.conf and change the size parameter:

# vzdump default settings

#tmpdir: DIR
#dumpdir: DIR
#storage: STORAGE_ID
#mode: snapshot|suspend|stop
#bwlimit: KBPS
#ionice: PRI
#lockwait: MINUTES
#stopwait: MINUTES
size: 4096
#maxfiles: N
#script: FILENAME
#exclude-path: PATHLIST

ISSUE: Basically vzdump is running out of memory and causing the backup of the particular container to fail. By default vzdump is set to use 500MB of memory and carrying out the above forces it to use 4096MB. Obviously take a look at memory usage and make sure 4096mb is available.