Varnish 4.0 Released

https://www.varnish-cache.org/lists/pipermail/varnish-announce/2014-April/000696.html

by nwjsmith • 12 years ago

136 41 12 years ago

varnish-cache.org

stefantalpalaru4• 12 years ago

Much of the VCL syntax has changed in Varnish 4.

Bullet, meet foot.

lkarsten• 12 years ago

For most users it is a 5-10 minute job, no sweat.

stefantalpalaru4• 12 years ago

Take a look at the instructions: https://www.varnish-cache.org/docs/trunk/whats-new/upgrading...

personZ• 12 years ago

The biggest impact of these sorts of changes are future users who are trying to get their first configuration going, following various web tutorials. Many of those tutorials are now misleading, but via the nature of accumulated web content it won't be changed any time soon.

Varnish is a nice project, but the lack of SSL significantly restricts its usefulness, especially in the "SSL everywhere" era. I've simply resorted to using nginx' proxy pass as the cache/load balancer.

ihsw• 12 years ago

It's not a point release, such compatibility-breaking changes should be expected.

gulbrandr• 12 years ago

Most of the changes seem to comes from a reorganization of the code, I think they were necessary.

perbu2• 12 years ago

The semantics are completely different which has to be reflected in the VCL. I think keeping compatibility at the cost of sanity is pretty dangerous and disregarding compatibility has been one of the success factors for the Linux kernel.

stefantalpalaru4• 12 years ago

disregarding compatibility has been one of the success factors for the Linux kernel

It's actually the other way around. Linus Torvalds dixit[1]:

"One of the core kernel rules has always been that we never ever break any external interfaces. That rule has been there since day one, although it's gotten much more explicit only in the last few years. The fact that we break internal interfaces that are not visible to userland is totally irrelevant, and a total red herring."

[1]. https://plus.google.com/115250422803614415116/posts/hMT5kW8L... - second comment

dwb2• 12 years ago

Backwards compatibility is vastly overrated, especially when the changes are as modest as the ones that I can see for Varnish 4. Sweep away the cruft. Make things better.

stefantalpalaru4• 12 years ago

How many development hours have been wasted because of Python 3, Perl 6, Lua 5.2, any new Django version, Ruby 1.9, Rails 4, jQuery 1.9, Bootstrap 3, etc. ?

Backwards compatibility is as simple as not wasting everybody's time. It should be high on the priority list, right under security and above performance. I like Linus' stance on the issue and I'm sure every developer dealing with syscalls appreciates it as well.

ruben_varnish9• 12 years ago

Don't forget the Varnish 4.0 Release Party on April 29th - http://v4party.varnish-cache.org #v4rp

smonte• 12 years ago

A bit off topic, but Varnish seems to have a valid point about using Varnish and SSL.

https://www.varnish-cache.org/docs/trunk/phk/ssl.html

"There is no other way we can guarantee that secret krypto-bits do not leak anywhere they should not, than by fencing in the code that deals with them in a child process, so the bulk of varnish never gets anywhere near the certificates, not even during a core-dump."

I came across this when looking for https support few weeks ago.

ruben_varnish9• 12 years ago

Indeed.

Via one of PHK's latest tweets:

https://twitter.com/bsdphk/status/453623583256760321

You can see (video) another of his comments regarding OpenSSL from his KeyNote at FOSDEM: http://ftp.belnet.be/FOSDEM/2014/Janson/Sunday/NSA_operation...

Dewie• 12 years ago

Watching that what-is-varnish video, I was surprised that this seems to be a Norwegian company. The narrator had an American (New England?) accent, not a naive/jovial Norwegian accent.

ruben_varnish9• 12 years ago

That is correct. We wrote the script and had a native English speaker reading it for us ;-)

Even if we have some colleagues who are from New England, we are a pretty multi-cultural Norwegian headquartered company as you can see in our site: https://www.varnish-software.com/about-us

Try the "What's coming in Varnish 4.0?" Hangout on Air video for a change: https://www.youtube.com/watch?feature=player_detailpage&v=St...

You will then heard our amazing mix of accents :-)

galenko4• 12 years ago

Can anyone who actually understands what the upgrade document states do a how to or a straight modification of a popular vcl, so people who don't have as much experience and pretty much just use these default vcl files?

Here's one that I and a few of my friends use routinely:

https://github.com/ewanleith/Wordpress-Server-Configuration-...

Like where do I start if I want to use this thing with 4.0?

vcl_fetch needs to be renamed, will this work if I just rename it and add vcl version to the top?

ruben_varnish9• 12 years ago

You need to read the documentation on this and understand it:

https://www.varnish-cache.org/docs/4.0/whats-new/index.html

Otherwise you should just be using a popular file from around the web. Take a look at the Varnish Utilities Directory:

https://www.varnish-cache.org/utilities

There you can find two of the best resources for ready to go VCL (for now Varnish 3 only):

https://github.com/slashsBin/nuCache

https://github.com/mattiasgeniar/varnish-3.0-configuration-t...

I am sure that if you ask nicely, the project members of these efforts might just give you a hand and upgrade to VCL 4.0 syntax a usable Wordpress template. Be willing to test and contribute back with whatever you can though.

galenko4• 12 years ago

Or if I currently don't have the time to do this, I have to either stop using varnish completely or not upgrade.

I get the whole needing to drop backwards compatibility thing, but without an idiot-proof way of upgrading, you're sentencing users like me, who use Varnish as a sprinkle of magic on the server.

Some examples of before/after of actual vcl files are a must in my opinion.

phkamp• 12 years ago

We are aware that there will be some head-scratching, that's why this is a 4.0 release rather than 3.1 or 3.5.

The two big changes which will affect the VCL you link are:

Purge is now treated as a special kind of transaction, which should make life easier for everybody using it.

And the client/backend split.

vcl_fetch{} in general becomes vcl_backend_response{} whereas the stuff usually done in both vcl_pass{} and vcl_miss{} becomes vcl_backend_fetch{}

Hope this helps.

PS: And yes, I wrote Varnish, and I'm very interested in any bugs, problems, or just plain stupidities you may find.

galenko4• 12 years ago

First of all, kudos, Varnish is an amazing piece of kit and hat's off to you sir.

However, I've been where you are and know how you feel, what you've said makes perfect logical sense to you, in your mind these are clear instructions on what should be done, but they still mean very little to someone who's completely new to this (even though they've been using Varnish for a good while now).

I'm a WordPress dev (I know, but it pays the bills), but I have been put between a rock and a hard place, so now I'm also responsible for setting up DO droplets for standalone websites. The reason I use Varnish is simplicity: apt-get install, wget on a WordPress vcl file, change a port and we're saving ram and can serve to 6x-10x concurrent users than before on straight nginx.

Thing is, I'm not alone in this use case, I know several people, who adore the magic and ease of use of Varnish. None of us know the insides, but we're can copy-paste and change a few things.

We respect and understand the need for dropping backwards compatibility, but all believe that the upgrade docs desperately need some examples.

I know it's the language of the devil, but the docs and the examples are definitely very usable to complete newbies: http://php.net/manual/en/function.date.php

Your docs are great for someone who has the time to read them all and learn all about Varnish, like a book, but (with no disrespect) borderline useless to someone who's got deadlines and a ton of work and simply has no time to learn this system that he's been relying on for a while.

brunoqc• 12 years ago

I don't know much about caching.

Does this work when serving dynamic content? I mean in a situation where your user absolutely need to see an up-to-date version of your data.

theg2• 12 years ago

Typically you serve up that content separately from the static content. We use it where it doesn't cache for logged in users but is on a rolling cache otherwise. Page updates invalidate the cache immediately as well.

On a dynamic site with user content, you're going to be using some sort of object caching depending on your framework and language of choice, Varnish is great for news sites and things of that nature though.

byoung2• 12 years ago

You can also cache some content on a page, even for logged-in users, and add in the dynamic parts using ESI. For example an ecommerce site could have a category page cached, and have one section at the top that says "Hello, John Doe" generated dynamically and added in using ESI.

https://www.varnish-cache.org/trac/wiki/ESIfeatures

brokentone• 12 years ago

No. This makes dynamic content static, by definition. However, you can exempt certain content from cache, exempt certain people from cache, exempt certain pieces of certain content from cache, or any combination. You can also invalidate cache when content changes (if you're able to do this absolutely, this is effectively dynamic), or set low TTLs to not have new content roll in on a certain time basis.

workhere-io• 12 years ago

Varnish is extremely configurable regarding that. Not only can you cache certain paths and leave others dynamic, but you can actually cache pages while leaving certain HTML elements on the page dynamic. E.g., let's say you have a mostly static page, but with the username on top ("you are logged in as brunoqc"). You can tell Varnish to cache the page and leave the HTML element containing the username dynamic.

ryankshaw• 12 years ago

"Full support for streaming objects through from the backend on a cache miss. Bytes will be sent to 1..n requesting clients as they come in from the backend server." is an awesome feature in and of itself. thank you varnish team, this looks like a great release.

Varnish 4.0 Released

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