> > Hi, > > > > I am experiencing slow logins and sudo authentication for servers joined to > > my FreeIPA domain. I have been following the other recent thread on slow > > logins and believe my issue is different. > > > > I have replication setup with 2 FreeIPA servers at each of 3 sites. The > > replication is working well and I am able to login correctly on client > > servers with correct sudo permissions etc. Logins seem to take a long time > > however. There seems to be some kind of DNS/connection timeout issues, see > > the example below where the client times out on the auth01 server, then > > retries and connects. I have also seen it switch to an alternate IPA server > > on timeout. Total delay in this example is about 10 seconds however it can > > take longer (approx 30 seconds). It is worth mentioning that client servers > > in each site cannot connect to IPA servers is a different site - however in > > the example below the auth01 IPA server is in the same site as the client > > server. I'm not sure if there is any way to make the IPA clients site aware > > so they prefer to log in to a local server? > > > > > > On the IPA servers themselves there is no noticeable delay and once I have > > authenticated with sudo once, subsequent attempts in the same login are > > also near instant. I have not been able to find any reason for this delay > > in any logs (which probably just means I'm not looking in the right place). > > > > > > DNS servers are running on each IPA server and responding well whenever I > > have tested. > > > > > > IPA Servers: CentOS 7.2.1511 running IPA 4.2.0 (from standard CentOS repo) > > > > Client servers: Ubuntu 14.04 running IPA 3.3.4 (From standard Ubuntu repo) > > > > > > Any comments or suggestions greatly appreciated. > > > > > > Thanks, > > > > Neal. > > > > > > Example sssd log for a "sudo -l" attempt. > > > > (Mon Aug 1 14:39:59 2016) [sssd[be[fqdn.com]]] [krb5_child_timeout] > > (0x0040): Timeout for child [7430] reached. In case KDC is distant or > > network is slow you may consider increasing value of krb5_auth_timeout. > > (Mon Aug 1 14:39:59 2016) [sssd[be[fqdn.com]]] [krb5_auth_done] (0x0020): > > child timed out! > > These debug messages seem to be telling you what the problem is. Have > you tried how long does it take to kinit (preferably with > KRB5_TRACE=/dev/stderr prepended) ?
Hi Jakub, Thanks for your response and sorry for my delay in replying. kinit takes between 2 and 25 seconds to complete - the KRB5_TRACE option shows it trying a random auth server, timing out and trying another random server until it picks a local server which then completes almost immediately. This seems to confirm that the problem is simply the server tries to authenticate against a FreeIPA server that is unreachable and times out causing the randomly slow logins. Given 6 auth servers with only 2 on each site there is a ~ 10% chance of hitting 3 bad servers in a row before login succeeds - if each takes 20 seconds that would explain the random login times of a few sec - 1 minute. If I enter the local kdc servers manually in the realm section of krb5.conf then ssh logins always happen in < 2sec - however I would prefer to avoid the manual step of configuring and updating this (planning to expand out to a few hundred servers over 4-5 sites). Manually setting these is likely to lead to mistakes and it just feels inelegant compared to DNS SRV records. I have seen https://www.freeipa.org/page/V4/DNS_Location_Mechanism which looks good but is a proposal from 2013 with no indications that it has actually been developed. I was also very interested by https://www.freeipa.org/page/Howto/IPA_locations which would be perfect - except the "ipa location-add" commands do not seem to be recognised by my FreeIPA installs. Am I missing a better way to handle the case of multiple locations with clients in Location A being unable to authenticate against FreeIPA servers at location B? Any suggestions greatly appreciated. Thanks, Neal.
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