Reduce Proxmox LXC Backup Size and Time

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Reduce Proxmox LXC Backup Size and Time

Category : How-to

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Proxmox backs up guests byte-for-byte in a compressed archive. Looking at LXC backups specifically, the file system is compressed into the target backup file with just a few exceptions – temp files aren’t included. You can also add your own exceptions by editing the vzdump.conf to exclude specific file patterns.

All that said, one of the biggest disk space wasters is the cache directory for apt which caches the installation packages for software you have installed. This can generally be safely removed on internet connected machines which will reduce your overall backup size.

For example, a newly created Debian LXC that’s been recently updated shows a total of 206MB of disk used.

After clearing this with the command apt-get clean we can see the space has mostly been freed.

Considering this whole container is only consuming approximately 1GB of disk space, 200MB is quite significant.

vzdump hooks

Now we can see how much space we can save, we need to make Proxmox issue the apt-get clean command before it creates the backup of our container.

vzdump, the utility which Proxmox uses to perform backups has the ability to call a script for various stages of the backup process – these stages are:

  • backup-start
  • backup-end
  • backup-abort
  • log-end
  • pre-stop
  • pre-restart
  • post-restart

We can use these hooks to run our own commands at any of these points of the backup. For the goal of this blog post, we want to run the apt-get clean command at the point of backup-start.

Create a script on your Proxmox host with the following content:

Now edit your vzdump.conf file and add the following line to point to your new script. Remember to change the location of where your script is – I’ve just saved mine in /root/.

 


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Rename a Proxmox Host

Category : How-to

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Renaming a Linux server’s hostname is usually a trivial task, and that’s no Different to a Proxmox server providing it’s not part of a cluster. If your machine is in a cluster then things get a bit more complicated and that’s a blog subject for another day.

For a single node machine it’s simple – Proxmox is Debian under the hood so simply follow the usual Debian process:

Change the hostname file to contain your new hostname

To save having to restart, you can also run the hostname command to implement the change on a running machine. Otherwise you’ll need to reboot your server to pick up the change.

Next, edit your /etc/hostname file and change all occurrences of the old hostname with the new one.


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Proxmox 5.0 is now available

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proxmox logo gradToday, the Proxmox VE team have released a new version of Proxmox, incrementing the major version to 5.0!

The new version packs in a raft of new features, the headline being the new Replicated Storage feature which enables batch style synchronisation of local storage volumes across servers.

You can download the ISO from https://www.proxmox.com/en/downloads/item/proxmox-ve-5-0-iso-installer

Highlights of the 5.0 release:

  • Based on Debian Stretch 9.0
  • Kernel 4.10.15
  • QEMU 2.9
  • LXC: update to 2.0.8
  • New asynchronous Storage Replication feature (needs ZFS, technology preview)
  • New/updated LXC templates (Debian, Ubuntu, CentOS, Fedora, OpenSUSE, Arch Linux, Gentoo and Alpine)
  • Updated/improved noVNC console]
  • Ceph v12.1.0 Luminous (technology preview), packaged by Proxmox
  • Live migration with local storage
  • GUI improvements
    • USB und Host PCI address visibility
    • improved bulk and filtering options
  • Improved installation ISO
  • Importing Qemu/KVM_Virtual_Machines#_importing_virtual_machines_from_foreign_hypervisors
  • Improved reference documentation with screenshots
  • Countless bug fixes and package updates

Upgrade

Before updating, make sure all your VM’s have been stopped, both LXC and KVM. Ensure you have the required repository entries for apt. You’ll either need a valid license key or to add the less stable pve-no-subscription repository.

Update your apt for Debian, edit /etc/apt/sources.list and replace it with:

And your Proxmox repository source /etc/apt/sources.list.d/pve-enterprise.list to the below. See Proxmox 3.1 package/ updates manager (this also works for version 5.x) for more information.

Run the below commands on each server in your cluster.

Restart all Proxmox servers to complete the installation.


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Start/ Stop Container Using The Proxmox Web API in Bash

Category : How-to

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The Proxmox Web API can perform any actions available in the front end Web. By implementing a REST API, all commands have been exposed and can be used programatically.

In this example we’ll use Bash to call the Proxmox Web API with our authentication token to start and stop an existing LXC Container.

See this post for an introduction to the Proxmox Web API, including all available API commands.

To issue API requests you’ll need to ensure you have already generated an authentication ticket which is described in Parse Proxmox Web API authentication ticket and the CSRFPreventionToken in Bash.

Once you have the authentication ticket you’ll need to call the Proxmox API using curl and parse the result. Use the below scripts and substitute the values as required:

Start an LXC Container

  • TICKET is the authentication ticket that was produced in the Parse Proxmox Web API authentication ticket and the CSRFPreventionToken in Bash post. Ideally you would programatically call the authentication routine and then pass the values straight into the below API calls.
  • CSRF is produced in the same way as TICKET. It’s actually only required when writing data to the API but there is no harm in always including it.
  • HOST is the host or IP address of the Proxmox server.
  • NODE is the node name of the Proxmox server that the LXC Container resides on.
  • TARGET_VM  is the VMID of the LXC Container.

If $START_TASK_RESULT doesn’t come back with null or empty then the command has successfully executed.

Stop an LXC Container

Stopping a VM in Proxmox is very similar to starting one, with just a slight change to the API URL call. All other options are the same as the above section ‘Start an LXC Container’.

If $STOP_TASK_RESULT doesn’t come back with null or empty then the command has successfully executed.


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Getting Started With Proxmox HTTP API Commands

Category : How-to

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Proxmox has 2 API access points that can be used to control your Proxmox server and virtual guests. One of the API access points is using the command line, which you’re likely already familiar with. The other is the HTTP web API which is exposed as part of the WEB GUI on port 8006.

The Proxmox uses a JSON data format for returning data that can easily be parsed programmatically. Every command available to the pvesh command line command are available to the web based API as they share the same endpoint.

The endpoint for the Web API can be called using anything that can send and receive web based requests. We’ll use curl for the below examples. The endpoint to call would be similar to below – be sure you substitute yourip for the IP or hostname of your Proxmox server.

API Authentication

The next step is to authenticate your API requests with the Proxmox server. API authentication uses the same mechanism that logging into the Web GUI uses and requires a username, password and security realm.

Authentication is based on a token method which provides a ticket that must accompany all API requests except for the request that generates the token. A username and password will not be accepted for authentication with all other API requests. In addition, any requests that POST or write to the API endpoint must contain a CSRF Prevention Token.

To obtain an authentication token, run the below curl command and substitute your values as required – this example uses the root user and the default PAM realm.

Example output:

The two interesting parts here are the ticket value and the CSRFPreventionToken and should be parsed out for use in later requests.

A token is valid for 2 hours and should be re-requested when it expires. Alternatively each request could generate it’s own token, however this generates added overhead.

List of Proxmox API Requests

pvesh is a command line utility can be used to perform the same actions as the web based API. You can, therefore, use the pvesh command to list all the possible API calls and navigate through the API call tree.

You can then list the available commands from the root of the API using ls and then change into one of the child paths using cd. You can navigate throughout the whole API tree using these two methods to see what commands are available for calling. This is often the best way to get started with the Proxmox API.

Examples of API Requests

As stated earlier, all operations available in the Proxmox Web GUI can be performed through the API. Here are a few examples of API requests using Bash:


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Parse Proxmox Web API authentication ticket and the CSRFPreventionToken in Bash

Category : How-to

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The Proxmox Web API can perform any actions available in the front end Web. By implementing a REST API, all commands have been exposed and can be used programatically.

The API is secured using a token based method which provides a ticket that must accompany all API requests except for the request that generates the token. The token is generated from an API call containing a username, password and security realm.

In this example we’ll use Bash to call the Proxmox Web API, authenticate with the root Proxmox user and parse the response for use in later API requests. Note that it’s not good practice to use the root account for API calls due to the security implications.

See this post for an introduction to the Proxmox Web API.

Add this function to the top of your Bash script. This will be used to parse the JSON using standard Bash calls to obtain the information we need.

The next step is to call the Proxmox API using curl to obtain our authentication token. Use the below script and substitute the values as required:

  • PROX_USERNAME is the username and security realm used to log into the Proxmox Web front end. This must be a valid user with the required permission to make the calls you need.
  • PROX_PASSWORD is the password for the above user. You must escape any special characters as usual in Bash.
  • HOST is the host or IP address of the Proxmox server.

And that’s all there is to it! You can use the variables $TICKET and $CSRF in later requests. Keep in mind that a valid ticket is only valid for 2 hours, after that you’ll need to create a new one.