Re: CARP

Farooq Ashraf wrote:

> running MS Proxy. Now, the administrator of the MS Proxy wants me to
> configure CARP and join the array that he has.
>
> How to do this in squid? I have seen a compile time option to
> --enable-carp. I have done that. But what to do after that?

Good question since Squid does not actually yet implement CARP, only the
CARP hashing method for request routing within a CARP like array with
all the array parameters hardcoded into squid.conf on each member.

Joining as a member in a MS Proxy CARP array will never be possible I
guess as CARP does not define how member caches notify each other of
it's existence and leave this to the implementator. AFAIK MS is using
MS-Proxy internal Windows RPC calls which will be a bit awkvard to
integrate into non-MS products..

Having Squid as a CARP enabled child cache to a parent CARP array is at
this time not possible since it is not implemented with parent arrays in
mind.

For Squid someone should implement:
a) A carp client, reading the array table of a parent CARP array and
properly route requests to it.

b) A generator of the above mentioned carp table for being used by
clients/child caches when running Squid as a CARP array.

c) Possibly some way that CARP array member registrations can be
propagated within an single CARP cluster, without having to edit the
configuration of each and every member. Could for example be done by
introducing the concept of "trusted CARP master", and make use of the
carp client code to parse the array table retreived from the master(s)
to build the list of other CARP members.

d) And to redefine cache_peer CARP specifications to not crash the
normal parent/sibling relation types when --enable-carp is used, to
allow a binary compiled with CARP support to be used in other
configurations.

If you or anyone else feels interested in getting this done please
contact squid-dev@squid-cache.org. Guidance to the code will be provided
so don't worry if you don't think you know the Squid code enought.
Modest level of C programming skills are required.

--
Henrik Nordstrom
Squid hacker