In this release we add a new feature for upgrading your Varnish version to Varnish 6. We will be installing Varnish version 6.1.1-1+deb10u1 when you upgrade your Varnish version to 6.
Using Varnish 6
Upgrading your Hypernode to Varnish 6 is an easy process, but should be handled with some caution. The Varnish team says “6.0 is actually not that scary, because most of the changes are either under the hood or entirely new features.” in the official changelog for Varnish 6.0.
You can verify your current Varnish version by running the command hypernode-systemctl settings varnish_version:
Make sure to read the official documentation for upgrading to Varnish 6 to ensure a smooth transition from Varnish 4 to Varnish 6.
Enable Varnish
Make sure to enable Varnish before you can use Varnish 6. This is as simple as running the following command on your Hypernode: hypernode-systemctl settings varnish_enabled True.
Upgrading to Varnish 6
Upgrading is as easy as running hypernode-systemctl settings varnish_version 6.0. However, changing your Varnish version will unload your currently active VCL. Before upgrading, you’ll see the following warning:
Take proper precautions before upgrading. As the warning mentions, make sure to make a backup of the /data/var/varnish/default.vcl config file before upgrading from Varnish 4.0 to ensure your Varnish configuration is not lost. After upgrading, make sure you load your VCL into the upgraded Varnish in the usual manner. Check out our support documentation for loading in Varnish VCL.
Differences between Varnish 4 and Varnish 6
Most features in Varnish 4 are still compatible in Varnish 6, which makes upgrading a feasible task. Only some features are removed like the cli_buffer configuration variable (which was deprecated in Varnish 5.2 and removed in Varnish 6). We updated the global Varnish configuration to match the new Varnish 6 requirements.
Using Varnish 6 is more or less the same experience as using Varnish 4. You load your VCL configuration with varnishadm vcl.load <vcl_file> <vcl_name> and use it with varnishadm vcl.use <vcl_name>. Most new features in Varnish 6 is in additional capabilities of configuring your VCL. Check out the official changelog for Varnish 6.0 to read up on all new features.