I recently ran the usual
sudo yum update, which included an upgrade of FreeIPA from version 4.4 to version 4.5. However, the upgrade reported that it failed, so I tried to run it manually afterwards:
$ sudo ipa-server-upgrade
The command above timed out, so I ran it again in verbose mode:
$ sudo ipa-server-upgrade --verbose
With the extra output, I saw it was getting stuck on the following before timing out:
ipa: DEBUG: wait_for_open_ports: localhost [8080, 8443] timeout 300
Neither 8080 nor 8443 are on the list of FreeIPA protocols/ports:
TCP 80, 443: HTTP/HTTPS
TCP 389, 636: LDAP/LDAPS
TCP 88, 464: kerberos
TCP 53: DNS
UDP 88, 464: kerberos
UDP 53: DNS
UDP 123: NTP
So what was going on?
I checked to see if those ports were listening:
$ sudo lsof -i TCP -P ... TCP *:8080 (LISTEN) TCP *:8443 (LISTEN) ... $ sudo lsof -i TCP ... TCP *:webcache (LISTEN) TCP *:pcsync-https (LISTEN) ...
The ports were listening, so why the timeout? Fortunately I found someone else describing a similar problem on the FreeIPA mailing list, with this reply from Alexander Bokovoy, one of the FreeIPA developers:
I’m a bit tired to repeat this multiple times but FreeIPA does require IPv6 stack to be enabled in the kernel. We absolutely do. If you don’t use IPv6 stack, disable it on specific interfaces. However, there is a practical problem with the way how glibc DNS resolver works: in default configuration it always prefers IPv6 answers to IPv4 because this is actually a policy of RFC3484. As result, if you have ::1 in /etc/hosts, it will be returned first. If you don’t have ::1 on any of your interfaces (‘lo’ is a typical one), then apps cannot contact ::1 (localhost) even if those apps that use IPv6 bind to all interfaces.
FreeIPA uses modern APIs provided by glibc to listen on both IPv6 and IPv4. It simply means that FreeIPA servers bind to IPv6 addresses (on all interfaces or on a specific one, if needed) and treat IPv4 as mapped ones because IPv6 and IPv4 share the same port space on the same machine. This works transparently thanks to glibc and is a recommended way to write networking applications. See man ipv6(7) for details.
Following that suggestion, I deleted the following line from
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
Sure enough, that solved the problem! This seems like a good idea for anyone who has disabled IPv6, even if you’re not running FreeIPA. Why include an entry in your hosts file that you know doesn’t work?
I had another FreeIPA server, this one running on an underpowered VM (1GB RAM, 1 CPU). Even after removing the IPv6 entry from /etc/hosts, the FreeIPA upgrade seemed to fail. The certmonger/dogtag processes would consume all of the system resources and it would freeze. All memory was in use and nearly all of the swap space as well. The CPU was running at 5000%. I gave up on it and ignored it for a while, and it turned out that letting it sit and process for a while helped. It seem to have worked itself out: FreeIPA is at the latest version and system resource utilization is very low.