squid doesn't function during/after HA failover
Per #2591, there is no spported way for squid to listen to a CARP VIP interface.
This means that HA isn't really HA for any scenario that enforces the use of a built-in proxy.
Per "Kill Bill"'s dismissive "use WPAD or whatever" answer, that solution ONLY works for desktop browsers that support WPAD "or whatever". Most non-browser software (e.g. pfsense itself!) requires a static proxy to be configured.
Simple solution: allow squid to service a VIP that fails over during a firewall failover event. Alternative solutions welcomed.
Without a way to do this, it is impossible (or rather, pointless!) to deploy pfSense as a high-availability solution in any environment that blocks direct outbound HTTP & HTTP/S. This is a bug, not a missing feature - it's equivalent to saying "HA works fine, just change your default gateway setting on every device".
#2 Updated by Kill Bill almost 5 years ago
P.S. If you want your "HA"/"failover", then stick
I obviously won't submit any such PR because it's BS that produces no real failover. As explained on the thread I linked you to on the other "bug" you filed.
#4 Updated by Adam Gibson about 2 years ago
Chris Buechler wrote:
should be possible, and a good idea, to list VIPs in the binding list.
As a workaround, can just bind it to localhost, and use a port forward to redirect traffic to the CARP IP and proxy port to 127.0.0.1.
I just use the following in the Advanced section of Squid General setup page where x.x.x.x is the virtual IP of the LAN.
Custom Options (Before Auth)
I also set the source address to the virtual address as well so that I can proxy traffic through VPN tunnels if needed. It is not needed for just Internet traffic though. The src IP will match the IPSEC tunnel and go through it. External traffic gets NATed properly as well.
Failover works fine for me with this config. Existing active connections in transfer get stuck of course but new connections go out properly.
#6 Updated by Adam Gibson about 1 year ago
Zeev Zalessky wrote:
any updates with this issue?
i have 200 vlans on my firewall and adding 200 lines with http_port is not good option.
IMHO additionally squid in HA configuration should start on active and stop on passive node like FRR.
Bill seems to have the opinion that if there is no way for the process state of the connections to migrate to the failover firewall's Squid proxy process, then it is not true HA so it is not worth using the VIP to do automatic failover of connections to the secondary's proxy server.
While I can understand the want to have a full 100% failover, Having that kind of requirement for failover would result in a lot of the HA stuff not meeting that strict requirement. Relayd being removed form pfsense 2.5 (because of upstream support) will also cause the same not true HA failover for the load balancing for those that have to transition from relayd to HAProxy. The process state of the connections in HAProxy will also not failover to the second instance of HAProxy during a HA failover causing the same issue that bill is mentioning happening to Squid. Current connections will not work but new connections will go to the new instance on the secondary firewall.
Knowing that Squid and HAProxy connections will not failover fully intact (because their internal state is inside the processes themselves so tcp state failover is not enough), that does not mean it is not useful for Squid or HAProxy to failover the TCP connections to the secondary instance to minimize downtime. Using the VIP for Squid or HAProxy is a very easy and good way to handle the failover knowing their limitations IMHO. A failover will impact current connections, but retries will go to the new Squid process automatically on the second Squid instance. This is without any config on the clients to try and deal with multiple Squid IPs/instances.
I disagree with Bill that the TCP state failover would hurt in this scenario. The TCP state failover will still help in this transition to make sure the client will get a TCP reset when the connection goes to the secondary firewall. The secondary will allow the existing connection's packets which will return a TCP reset because the TCP state of the process on the local system will no longer be valid causing the firewall IP stack to send a TCP reset. If the TCP state was not pushed to the secondary firewall, the secondary firewall would drop the packet causing more of a delay for the recovery.
To sum up, I think listing the VIP is a very good thing to help with HA failover for Squid without needing another NAT rule and listening on 127.0.0.1 or needing any custom config section to force http_port on the VIP. I have been using the custom config method now for a few years and it has been working well... with the limitation of knowing that existing connections will be reset but new connections will go to the secondary firewall's Squid instance and work.