Changes/UpdateToVarnish4

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Update varnish to version 4.0.x

Summary

Varnish Cache is a state of the art web cache. It is used to accelerate web content delivery. We want to update its major release from varnish 3.0.x to 4.0.x for fedora 21.

Owner

Current status

  • Targeted release: Fedora 21
  • Last updated: 2014-05-04
  • Tracker bug: <will be assigned by the Wrangler>

Detailed Description

Upstream recently released varnish-4.0.0 after three years of development. This new major upstream release sports large changes in the core of varnish, including several improvements for speed and stability, and better and more surrounding tools.

Benefit to Fedora

While varnish3 is the most used version of varnish in production environments, it is growing old. Varnish4 is newer, faster and better. Getting varnish4 in fedora 21 will make fedora a better development environment and test bed for varnish users and developers.

Also varnish version 3 will loose upstream attention as the developers will focus on the 4.0.x series release from now on.

Finally, EPEL7 will get varnish4. It would be a shame to be behind both upstream and EPEL.


Scope

  • Proposal owners: This is a quite isolated change. The only other package I know of that depends on varnish is varnish-agent, which will get a new upstream version compatible with varnish-4.0.0 any day. I am in contact with the fedora packager of varnish-agent to resolve this.
  • Other developers: N/A (not a System Wide Change)
  • Release engineering: N/A (not a System Wide Change)
  • Policies and guidelines: N/A (not a System Wide Change)

Upgrade/compatibility impact

As the syntax of the Varnish Configuration Language (VCL) has changed, users of varnish will have to change their VCL code to get varnish to work properly after the update. The changes neccesary are documented on the varnish-cache.org website, at https://www.varnish-cache.org/docs/4.0/whats-new/upgrading.html .

No functionality will be lost, but users will have to change their VCL.

How To Test

  • Testers should have at least 1GB available.
  • Building the package from rawhide source rpm runs a large set of regression tests, so doing that is preferable


User Experience

After the upgrade, and doing the necessary changes to VCL, varnish should deliver content as usual. High performance users may benefit from better performance. New tools with better capabilities, including better log filtering will be available.


Dependencies

varnish-agent, see above. We expect a new varnish-4.0.0 compatible upstream release shortly.


Contingency Plan

  • Contingency mechanism: Keep on varnish-3.0.x for fedora 21.
  • Contingency deadline: N/A (not a System Wide Change)
  • Blocks release? N/A (not a System Wide Change), Yes/No
  • Blocks product? N/A

Documentation

When upgrading from varnish version-3.0.x (fedora 20 and down), to varnish-4.0.x, VCL must be updated to match the new syntax. Upstream documentation available here: https://www.varnish-cache.org/docs/4.0/whats-new/upgrading.html


Release Notes

Fedora 21 will include an update of Varnish Cache to varnish-4.0. Varnish users must change their VCL to match the syntax changes for the 4.0 release. Details at https://www.varnish-cache.org/docs/4.0/whats-new/upgrading.html