FreeIPA - Recreate corrupted ds.keytab

If for some reason your ds.keytab has been corrupted, for example through time drift in the hardware clocks of your multi-master infrastructure, you'll find yourself with a non-working or very slow krb5kdc. However, this can be fixed fairly fast but you'll have to check your replicas for errors and maybe even replicate the whole infrastructure from a known good replica.

Let's get to fixing the corrupted ds.keytab first. All these steps will be done with your authentication services offline, so it's probably the safest to do all of the steps as root. Start by stopping the ipa services on the host:

 [archy@ipa02 ~]$ sudo su -  
 [root@ipa02 ~]# ipactl stop

Next up move the not-working keytab:

 [root@ipa02 ~]# mv /etc/dirsrv/ds.keytab /etc/dirsrv/ds.keytab-$(date +%Y-%m-%d)

In order to fix the keytab, a few services are required to run:

 [root@ipa02 ~]# start-dirsrv  
 [root@ipa02 ~]# systemctl start krb5kdc.service

Next login to the krb5kdc and export the dirsrv principal

 [root@ipa02 ~]# kadmin.local   
 kadmin.local: ktadd -k /etc/dirsrv/ds.keytab ldap/ipa02.archyslife.lan@ARCHYSLIFE.LAN 
 kadmin.local: quit

Now, change the permissions to pass the permission checks:

 [root@ipa02 ~]# chmod 600 /etc/dirsrv/ds.keytab  
 [root@ipa02 ~]# chown dirsrv.dirsrv

Verify the kvno version numbers from atleast 2 hosts. These must be the same on all hosts for the principal:

 [root@ipa02 ~]# kinit admin  
 Password for admin@ARCHYSLIFE.LAN:  
 [root@ipa02 ~]# kvno ldap/ipa02.archyslife.lan@ARCHYSLIFE.LAN  
 ldap/ipa02.archyslife.lan@ARCHYSLIFE.LAN: kvno = 8
  
 ---------- check from another host ----------  

 [root@ipa01 ~]# kinit admin  
 Password for admin@ARCHYSLIFE.LAN:  
 [root@ipa01 ~]# kvno ldap/ipa02.archyslife.lan@ARCHYSLIFE.LAN  
 ldap/ipa02.archyslife.lan@ARCHYSLIFE.LAN: kvno = 8

With everything looking good so far, verify that the ipa services start and stop as expected (optional, recommended):

 [root@ipa02 ~]# ipactl start  
 [root@ipa02 ~]# ipactl stop

If everything works and no errors are thrown, start the services for good.

 [root@ipa02 ~]# ipactl start

I've noticed this error appearing after patching the Hosts and having a time drift of the hardware clocks on the physical hosts even though they were synced with ntp and peering.

Feel free to comment and / or suggest a topic.

Comments

Dynamic DNS with BIND and ISC-DHCP

I personally prefer to work with hostnames instead of ip-addresses. If you have anything like freeipa or active directory, it will do that for you by registering the client you added to your realm to the managed dns and edit the records dynamically. We can achieve the same goal with just bind and isc-dhcp. I'll use a raspberry pi with raspbian 9 for this setup. So here is a quick tutorial on how to configure the isc-dhcp-server to dynamically update bind. First set a static ip to your server. [archy@ddns ~]$ sudo vim /etc/network/interfaces # interfaces(5) file used by ifup(8) and ifdown(8) # Please note that this file is written to be used with dhcpcd # For static IP, consult /etc/dhcpcd.conf and 'man dhcpcd.conf' # Include files from /etc/network/interfaces.d: source-directory /etc/network/interfaces.d auto eth0 iface eth0 inet static address 172.31.30.5 network 172.31.30.0 broadcast 172.31.30.255 netmask 255.255.255.0 ...

Push logs and data into elasticsearch - Part 2 Mikrotik Logs

This is only about the setup of different logging, one being done with Filebeat and the other being done with sending logging to a dedicated port opened in Logstash using the TCP / UDP Inputs. Prerequesites: You'll need a working Elasticsearch Cluster with Logstash and Kibana. Start by getting the Log Data you want to structure parsed correctly. Mikrotik Logs are a bit difficult since they show you Data in the interface which is already enriched with Time / Date. That means a message that the remote logging will send to Logstash will look like this: firewall,info forward: in:lan out:wan, src-mac aa:bb:cc:dd:ee:ff, proto UDP, 172.31.100.154:57061->109.164.113.231:443, len 76 You can check them in the grok debugger and create your own filters and mapping. The following is my example which might not fit your needs. Here are some custom patterns I wrote for my pattern matching: MIKROTIK_DATE \b(?:jan(?:uary)?|feb(?:ruary)?|mar(?:ch)?|apr(?:il)?|may|jun(?:e)?|jul(?...

LACP-Teaming on CentOS 7 / RHEL 7

What is teaming? Teaming or LACP (802.3ad) is a technique used to bond together multiple interfaces to achieve higher combined bandwith. NOTE: every clients speed can only be as high as the single link speed of one of the members. That means, if the interfaces I use in the bond have 1 Gigabit, every client will only have a maximum speed of 1 Gigabit. The advantage of teaming is, that it can handle multiple connections with 1 Gigabit. How many connections depends on the amount of your network cards. I'm using 2 network cards for this team on my server. That means I can handle 2 Gigabit connections at full rate on my server provided the rest of the hardware can deliver that speed. There also exists 'Bonding' in the Linux world. They both do the same in theory but for a detailed comparison check out this article about teaming in RHEL7 . To create a teaming-interface, we will first have to remove all the interface configurations we've done on the (soon to be) sla...

FreeIPA - Integrating your DHCPD dynamic Updates into IPA

I recently went over my network configuration and noticed that the dhcp-leases were not pushed into the IPA-DNS yet. So I thought, why not do it now. The setup is very similar to setting it up on a single bind instance not managed by IPA (I've already written a guide about this here ). My setup is done with the following hosts: ipa01.archyslife.lan - 172.31.0.1 inf01.archyslife.lan - 172.31.0.5 First of all, create a rndc-key: [archy@ipa01 ~]$ sudo rndc-confgen -a -b 512 This will create the following file '/etc/rndc-key' [archy@ipa01 ~]$ sudo cat /etc/rndc.key key "rndc-key" { algorithm hmac-md5; secret "secret_key_here=="; }; We also need to make named aware of the rndc-key and allow our remote dhcp server to write dns entries: [archy@ipa01 ~]$ sudo vim /etc/named.conf ... include "/etc/rndc-key"; controls { inet 172.31.0.1 port 953 allow { 172.31.0.5; } keys ...

Creating a pgpool-II based PostgreSQL Cluster

This time I'm going to do a small and quick walkthrough for a postgresql cluster install. I assume you have a clean install of CentOS 7.3 with all updates. The configuration itself is surprisingly simple. The enviroment I'm working with is: Node1: Hostname: pgsql01.archyslife.lan IP: 172.31.10.31 Member of IPA-Domain Selinux: enforcing Node2: Hostname: pgsql02.archyslife.lan IP: 172.31.10.32 Member of IPA-Domain Selinux: enforcing Cluster: Main Node: pgsql01.archyslife.lan Replica: pgsql02.archyslife.lan Virtual IP: 172.31.10.33 for the sake completeness I'll be adding a A-Record entry in the IPA-DNS. Let's start with the configuration of each node. First I will completely setup the Master without restarting the services, afterwards the replica will follow. Steps necessary for both nodes. Add the pgsql-repo to yum. [archy@pgsql01 ~]$ sudo yum -y install https://download.postgresql.org/pub/repos/yum/9.6/redhat/rhel-7-x86_64/pgdg-centos96-9.6...

Archy's Blog

Search This Blog