xCAT Configuration

 xCAT configuration is saved in a database which consists of many tables (command ‘tabdump’ can show a list of all tables). The default DB xCAT uses is ‘sqlite’. This can be changed to MySQL (MariaDB), PostgreSQL or others.

Different tables in xCAT DB are for different purposes. There are a handful of common tables which need to be configured for all kind of hardware but there are some specific tables which are only used for specific kind of environment. For example ‘ppc’ table will only be used when using Power PC based hardware and ‘prodkey’ table will only be used when installing MS Windows environment.

It’s time to configure common xCAT tables. Let’s do it.

tabedit site

Make sure you edit these lines. If these lines are not present then add new ones.

"dhcpinterfaces","10.0.0.11|enp0s3",,

"dnsinterfaces","10.0.0.11|enp0s3",,

"master","10.0.0.11",,

"nameservers","10.0.0.11",,

"domain","cluster.local",,

Note: You need to use the network interface which is set with IP ‘10.0.0.11’. In my case it is ‘enp0s3’

tabedit networks

The table should be looking like this

#netname,net,mask,mgtifname,gateway,dhcpserver,tftpserver,nameservers,ntpservers,logservers,dynamicrange,staticrange,staticrangeincrement,nodehostname,ddnsdomain,vlanid,domain,mtu,comments,disable

"cluster","10.0.0.0","255.255.255.0","enp0s3","<xcatmaster>",,"<xcatmaster>",,,,"10.0.0.151 10.0.0.175",,,,,,,"1500",,

It’s always a good idea to change ‘netname’ to a name which is easy to understand. Also add ‘dynamicrange’ for DHCP. Other fields are normally pre-filled.

Useful Notes: Since this is just a POC environment and we don’t need any IPMI or other networks i.e 10G or IPoIB (Infiniband). In real world these networks are normally required.

 tabedit hosts

Add all nodes with their IP addresses. This will help us in generating ‘/etc/hosts’ file.

  #node,ip,hostnames,otherinterfaces,comments,disable

"omaster","10.0.0.11",,,,

"compute001","10.0.0.101",,,,

tabedit noderes

#node,servicenode,netboot,tftpserver,tftpdir,nfsserver,monserver,nfsdir,installnic,primarynic,discoverynics,cmdinterface,xcatmaster,current_osimage,next_osimage,nimserver,routenames,nameservers,proxydhcp,syslog,comments,disable

"compute",,"xnba",,,,,,,,,,,,,,,,,,,

You can use ‘pxe’ instead of ‘xnba’ but ‘xnba’ is recommended as this supports more options than ‘pxe’

tabedit passwd

#key,username,password,cryptmethod,authdomain,comments,disable

"system","root","$6$9FdrtZiCetX4cV2G$JJlywIQZByWwVmiaGPAW0ZSChOTU0VIa5MybqMwwj8fr9.Fg9BGrcu1Nq/PpyVBt8r4shXPxzSwi5BkdtYwZq1",,,,

Password can be in plain text or encrypted. Encrypted password can be copied from ‘/etc/shadow’ file.

tabedit chain

#node,currstate,currchain,chain,ondiscover,comments,disable

"compute",,,,"nodediscover",,

This was the minimal table configuration. To deploy nodes an OS ISO needs to be copied to ‘omaster’ node. Type this command to get this done.

copycds CentOS-7-x86_64-Everything-2003.iso

This will copy the OS into ‘/install’ directory. The ISO doesn’t have to include ‘Everything’, normal ISO is good enough for installation.

Here you go. This is the least configuration we need to add.

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