[squid-users] grouping multiple cache peers possible?

[Alex Rousskov]

On 12/22/21 11:56 AM, roee klinger wrote:

> Currently, Squid is a bit problematic when dealing with many cach_peers, 
> it requires a lot of configurations for each cach_peer, which makes the
> configuration file big and takes a performance toll.

Consider merging multiple cache_peer_access rules for the same
cache_peer into one rule (using all-of and any-of ACLs).

You can also outsource peer selection to an external ACL, leaving one
simple cache_peer_access rule (with a single note ACL) for each
cache_peer in squid.conf.

And with some Squid code modifications, one can even let an external ACL
select the cache_peer to use without extra cache_peer_access checks.
This feature would be similar to the existing X-Next-Services routing
functionality in Squid adaptation code.

Finally, one can invest into optimizing/fixing Squid code to eliminate
unnecessary repeated cache_peer_access checks, probably saving a lot of
CPU cycles for Squid instances with many (or complex) cache_peer_access
rules.


Cheers,

Alex.

> On Wed, Dec 22, 2021 at 6:44 PM Alex Rousskov wrote:
> 
>     On 12/22/21 11:29 AM, roee klinger wrote:
>     > cache_peer 100.70.162.11 parent 16211 0 proxy-only default
>     name=proxy16211
>     > cache_peer 100.70.162.12 parent 16212 0 proxy-only default
>     name=proxy16212
>     > cache_peer 100.70.162.13 parent 16213 0 proxy-only default
>     name=proxy16213
>     > acl peer_group_162 peername_regex -i proxy162.*\b
>     >
>     > Followed by:
>     > cache_peer_access peer_group_162 allow admin162
> 
>     According to documentation, the cache_peer_access directive requires a
>     peer name (or a peer host name) as the second parameter. Your
>     configuration is using a string "peer_group_162", which is not a name of
>     any cache_peer.
> 
>     AFAICT, while you can use peername_regex to _match_ a group of
>     cache_peers, you still have to name a specific peer as the second
>     parameter of the cache_peer_access rule. That effectively defeats the
>     purpose of using peername_regex in this case! It was wrong for me to
>     point you in peername_regex direction.
> 
>     Your configuiration has to have at least one cache_peer_access rule for
>     each cache_peer.
> 
> 
>     Sorry,
> 
>     Alex.
> 
> 
>     > but I got an error:
>     > ERROR: /etc/squid/conf.d/admin_allow_peer.conf, line 4: No cache_peer
>     > 'peer_group_162'
>     >
>     > Should I use http_access instead? I am not sure how to use it, because
>     > peer_group_162 is an ACL, not a cache_peer.
>     >
>     > Also, is my regex entry correct? I am not sure if \b is supported, and
>     > if I should add the -i flag or not.
>     >
>     > Thanks alot.
>     >
>     > On Wed, Dec 22, 2021 at 5:27 PM Alex Rousskov wrote:
>     >
>     >     On 12/22/21 10:21 AM, roee klinger wrote:
>     >
>     >     > I have a group of about 6 cache peers:
>     >     >
>     >     >     cache_peer 100.70.162.11 parent 16211 0 proxy-only default
>     >     name=proxy16211
>     >     >     cache_peer 100.70.162.12 parent 16212 0 proxy-only default
>     >     name=proxy16212
>     >     >     cache_peer 100.70.162.13 parent 16213 0 proxy-only default
>     >     name=proxy16213
>     >     >
>     >     >     cache_peer 100.70.163.11 parent 16311 0 proxy-only default
>     >     name=proxy16311
>     >     >     cache_peer 100.70.163.12 parent 16312 0 proxy-only default
>     >     name=proxy16312
>     >     >     cache_peer 100.70.163.13 parent 16313 0 proxy-only default
>     >     name=proxy16313
>     >     >
>     >     >
>     >     > I would like to allow user162_acl access only to the peers
>     that ...
>     >     > have a name that starts with proxy162
>     >
>     >     According to documentation, a peername_regex ACL can do what
>     you want.
>     >
>     >     Alex.
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