Xen Bug: xen_net: Memory squeeze in netback driver (32bit PAE)

If you are receiving the following error in your logs while running a 32bit PAE Xen Kernel:

xen_net: Memory squeeze in netback driver

Then you need to do the following:

1. In your grub.conf (or other bootloader) set the Dom0 to a fixed size: dom0_mem=1024.

2. In /etc/xen/xend-config.sxp set dom0-min-mem to the same size as above.

3. Reboot

Basically what you are doing is ensuring that Dom0 will not be decreased in size, as when this happens it causes problems the the xen_net driver which can in turn cause network connectivity problems with your DomUs.

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Filed under: Uncategorized by — aaron @ 10:10 pm

Upgrading DomU Kernel HyperVM/Xen

First install both the Dom0 and DomU kernel by doing a yum upgrade.  Once you have done this, reboot the server into the new Dom0 kernel and run the following command (before you start each VPS on the server):

cd /usr/local/lxlabs/hypervm/httpdocs/; lphp.exe ../bin/misc/fixcentos5xen.php

Related posts

• Xen Bug: xen_net: Memory squeeze in netback driver (32bit PAE) (0)
• Where are the Xen log files? (0)
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• HyperVM/Xen nash-hotplug using 100% of resources (Debian) (0)
• error: xenconsole: Could not open tty `/dev/pts/2′: No such file or directory (0)

Filed under: Uncategorized by — aaron @ 9:42 pm

REVOLUTIONARY XEN VPS Plans! Starting at $20/month - Upto 4GB RAM, 400GB Storage

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Feel free to contact us at sales@crucialparadigm.com if you have any questions!

Related posts

• Where are the Xen log files? (0)
• Problems accessing Console on Xen virtual server (0)
• error: xenconsole: Could not open tty `/dev/pts/2′: No such file or directory (0)
• HyperVM: VM creation has failed. Reason: Could not download __path_program_ or no_template_and_could_not_download [] (0)
• Xen Bug: xen_net: Memory squeeze in netback driver (32bit PAE) (0)

Filed under: Uncategorized by — aaron @ 8:55 pm

Reconfiguring IP in XenServer via command line

If you need to reconfigure an IP address of XenServer via the command line.

xe pif-reconfigure-ip uuid= mode=static IP= gateway= netmask=

If using DHCP for assigning IPs, then,

#xe pif-reconfigure-ip mode=dhcp uuid=

If using STATIC then,

#xe pif-reconfigure-ip mode=static DNS= gateway=<IP of Gateway> IP= netmask= uuid=

If a server has multiple network cards you can use the following commands to assist in establishing the active link:

xe pif-plug uuid
xe pif-list

Related posts

• Xen Bug: xen_net: Memory squeeze in netback driver (32bit PAE) (0)
• Where are the Xen log files? (0)
• Upgrading DomU Kernel HyperVM/Xen (0)
• Problems accessing Console on Xen virtual server (0)
• HyperVM: Kernel image does not exist: /boot/hypervm-xen-vmlinuz (0)

Filed under: Uncategorized by — aaron @ 5:52 pm

HyperVM: Kernel image does not exist: /boot/hypervm-xen-vmlinuz

Error: HyperVM: Kernel image does not exist: /boot/hypervm-xen-vmlinuz

To fix this error, login to the HyperVM slave and run the following:

# cd /usr/local/lxlabs/hypervm/httpdocs

# lphp.exe ../bin/misc/fixfc6xen.php

Related posts

• Xen Bug: xen_net: Memory squeeze in netback driver (32bit PAE) (0)
• Where are the Xen log files? (0)
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• linux-utils: update-rc.d: /etc/init.d/hwclock.sh: file does not exist (0)
• HyperVM: remote_authentication_failed / Can’t reset password in HyperVM (0)

Filed under: Uncategorized by — aaron @ 7:59 am

Problems accessing Console on Xen virtual server

If you are having trouble accessing all virtual server’s (DomUs) via their consoles on a Xen server, you can easily resolve this by restarting xenconsoled. For example:

# xenconsoled –log=all –log-dir=/var/log/xen/console/

Related posts

• Where are the Xen log files? (0)
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• What is HVM? (0)

Filed under: Uncategorized by — aaron @ 3:05 am

HyperVM: VM creation has failed. Reason: Could not download __path_program_ or no_template_and_could_not_download []

HyperVM with Xen Error when trying to rebuild a VDS, or when trying to setup a new VDS:

VM creation has failed. Reason: Could not download __path_program_

Or

no_template_and_could_not_download []

Solutions:

1.  Ensure firewall is not running on slave, or incoming and outgoing port 8889 is allowed.
2. Set the permissions to 644 to the template (which is creating the error message) on the master server in the /home/hypervm/xen/template directory.
3. Ensure that the FQDN (fully qualified domain name) for the HyperVM master server (Servers -> localhost -> Information) is resolving to the correct IP.

Related posts

• Xen Bug: xen_net: Memory squeeze in netback driver (32bit PAE) (0)
• Where are the Xen log files? (0)
• error: xenconsole: Could not open tty `/dev/pts/2′: No such file or directory (0)
• Xen DomU: 4gb seg fixup, process (0)
• Upgrading DomU Kernel HyperVM/Xen (0)

Filed under: Uncategorized by — aaron @ 10:12 pm

HyperVM/Xen nash-hotplug using 100% of resources (Debian)

Some of the default HyperVM templates have an issue with nash-hotplug taking a large amount of resources (usually 99%). If you are having this issue, a quick an easy way to fix this is add the following to /etc/rc.local on the guest VDS:

pkill -9 nash

This is a temporary fix, until a more permanent one is provided by Lxlabs/HyperVM. This problem is supposedly already fixed in CentOS 4, however seems to still appear in Debian 3. For debian, do the following:

Open up /etc/init.d/local and add:

#!/bin/bash
pkill -9 nash

Then run the following:

chmod 755 /etc/init.d/local
update-rc.d local start 98 2 3 4 5 .
mkdir /etc/rc.d/
ln -s /etc/init.d/local /etc/rc.d/rc.local

Related posts

• Xen Bug: xen_net: Memory squeeze in netback driver (32bit PAE) (0)
• Where are the Xen log files? (0)
• Upgrading DomU Kernel HyperVM/Xen (0)
• HyperVM: Kernel image does not exist: /boot/hypervm-xen-vmlinuz (0)
• error: xenconsole: Could not open tty `/dev/pts/2′: No such file or directory (0)

Filed under: Uncategorized by — aaron @ 5:10 pm

Where are the Xen log files?

The Xen/Xend/xm log files can be found: /var/log/xen

Related posts

• error: xenconsole: Could not open tty `/dev/pts/2′: No such file or directory (0)
• HyperVM: VM creation has failed. Reason: Could not download __path_program_ or no_template_and_could_not_download [] (0)
• Xen Bug: xen_net: Memory squeeze in netback driver (32bit PAE) (0)
• Upgrading DomU Kernel HyperVM/Xen (0)
• Problems accessing Console on Xen virtual server (0)

Filed under: Uncategorized by — aaron @ 10:22 pm

error: xenconsole: Could not open tty `/dev/pts/2′: No such file or directory

Error: xenconsole: Could not open tty `/dev/pts/2′: No such file or directory

If you come across this error when using xm console, then you can do the following:

In that case, make sure that xenconsoled is running.

ps aux |grep xenconsoled

If is not running, just execute

xenconsoled

Now you should be able to login to the VPS using xm console.

What is xenconsoled? xenconsoled is the daemon which enables you to console into each virtual server on a Xen host.

Related posts

• Where are the Xen log files? (0)
• HyperVM: VM creation has failed. Reason: Could not download __path_program_ or no_template_and_could_not_download [] (0)
• Xen Bug: xen_net: Memory squeeze in netback driver (32bit PAE) (0)
• Upgrading DomU Kernel HyperVM/Xen (0)
• Problems accessing Console on Xen virtual server (0)

Filed under: Uncategorized by — aaron @ 6:58 pm