.. _setup_service_node_stateless_label: Diskless (Stateless) Installation ================================= .. note:: The stateless Service Node is not supported in Ubunti hierarchy cluster. For Ubunti, skip this section. If you want, your Service Nodes can be stateless (diskless). The Service Node must contain not only the OS, but also the xCAT software and its dependencies. In addition, a number of files are added to the Service Node to support the PostgreSQL, or MySQL database access from the Service Node to the Management node, and ssh access to the nodes that the Service Nodes services. The following sections explain how to accomplish this. Build the Service Node Diskless Image ------------------------------------- This section assumes you can build the stateless image on the management node because the Service Nodes are the same OS and architecture as the management node. If this is not the case, you need to build the image on a machine that matches the Service Node's OS architecture. * Create an osimage definition. When you run ``copycds``, xCAT will only create a Service Node stateful osimage definitions for that distribution. For a stateless Service Node osimage, you may create it from a stateless Compute Node osimage definition. :: lsdef -t osimage | grep -i netboot rhels7.3-ppc64le-netboot-compute (osimage) mkdef -t osimage -o rhels7.3-ppc64le-netboot-service \ --template rhels7.3-ppc64le-netboot-compute \ profile=service provmethod=netboot postscripts=servicenode lsdef -t osimage rhels7.3-ppc64le-netboot-service Object name: rhels7.3-ppc64le-netboot-service exlist=/opt/xcat/share/xcat/netboot/rh/compute.rhels7.ppc64le.exlist imagetype=linux osarch=ppc64le osdistroname=rhels7.3-ppc64le osname=Linux osvers=rhels7.3 otherpkgdir=/install/post/otherpkgs/rhels7.3/ppc64le pkgdir=/install/rhels7.3/ppc64le pkglist=/opt/xcat/share/xcat/netboot/rh/compute.rhels7.ppc64le.pkglist postinstall=/opt/xcat/share/xcat/netboot/rh/compute.rhels7.ppc64le.postinstall postscripts=servicenode profile=service provmethod=netboot rootimgdir=/install/netboot/rhels7.3/ppc64le/compute * Configure mandatory attributes for Service Node osimage definition. The following attributes must be modified to suitable value: :: exlist otherpkglist pkglist postinstall rootimgdir #. Create the exlist, pkglist and otherpkglist file. xCAT ships a basic requirements lists that will create a fully functional Service Node. However, you may want to customize your service node by adding additional operating system packages or modifying the files excluded by the exclude list. Check the below files to see if it meets your needs. :: cd /opt/xcat/share/xcat/netboot/rh/ view service.rhels7.ppc64le.pkglist view service.rhels7.ppc64le.otherpkgs.pkglist view service.rhels7.ppc64le.exlist If you would like to change any of these files, copy them to a custom directory. This can be any directory you choose, but we recommend that you keep it /install somewhere. A good location is something like ``/install/custom/netboot/``. :: export OSIMAGE_DIR=/install/custom/netboot/rhels7.3-ppc64le-netboot-service mkdir -p $OSIMAGE_DIR cp /opt/xcat/share/xcat/netboot/rh/service.rhels7.ppc64le.pkglist $OSIMAGE_DIR cp /opt/xcat/share/xcat/netboot/rh/service.rhels7.ppc64le.otherpkgs.pkglist $OSIMAGE_DIR cp /opt/xcat/share/xcat/netboot/rh/service.rhels7.ppc64le.exlist $OSIMAGE_DIR And make sure that your ``otherpkgs.pkglist`` file has the following entries: :: xcat/xcat-core/xCATsn xcat/xcat-dep///conserver-xcat xcat/xcat-dep///perl-Net-Telnet xcat/xcat-dep///perl-Expect For example, for the osimage *rhels7.3-ppc64le-netboot-service*: :: xcat/xcat-core/xCATsn xcat/xcat-dep/rh7/ppc64le/conserver-xcat xcat/xcat-dep/rh7/ppc64le/perl-Net-Telnet xcat/xcat-dep/rh7/ppc64le/perl-Expect .. note:: You will be installing the xCAT Service Node RPM ``xCATsn`` on the Service Node, not the xCAT Management Node RPM. Do not install both. #. Create the postinstall script. xCAT ships a default postinstall script for stateless Service Node. You may also choose to create an appropriate /etc/fstab file in your Service Node image. : :: export OSIMAGE_DIR=/install/custom/netboot/rhels7.3-ppc64le-netboot-service cp /opt/xcat/share/xcat/netboot/rh/service.rhels7.ppc64le.postinstall $OSIMAGE_DIR vi $OSIMAGE_DIR/service.rhels7.ppc64le.postinstall # uncomment the sample fstab lines and change as needed: proc /proc proc rw 0 0 sysfs /sys sysfs rw 0 0 devpts /dev/pts devpts rw,gid=5,mode=620 0 0 service_ppc64le / tmpfs rw 0 1 none /tmp tmpfs defaults,size=10m 0 2 none /var/tmp tmpfs defaults,size=10m 0 2 #. Modify the Service Node osimage definition with given attributes. :: export OSIMAGE_DIR=/install/custom/netboot/rhels7.3-ppc64le-netboot-service chdef -t osimage -o rhels7.3-ppc64le-netboot-service \ exlist=$OSIMAGE_DIR/service.rhels7.ppc64le.exlist \ otherpkglist=$OSIMAGE_DIR/service.rhels7.ppc64le.otherpkgs.pkglist \ pkglist=$OSIMAGE_DIR/service.rhels7.ppc64le.pkglist \ postinstall=$OSIMAGE_DIR/service.rhels7.ppc64le.postinstall \ rootimgdir=$OSIMAGE_DIR/service lsdef -t osimage -l rhels7.3-ppc64le-netboot-service Object name: rhels7.3-ppc64le-netboot-service exlist=/install/custom/netboot/rhels7.3-ppc64le-netboot-service/service.rhels7.ppc64le.exlist imagetype=linux osarch=ppc64le osdistroname=rhels7.3-ppc64le osname=Linux osvers=rhels7.3 otherpkgdir=/install/post/otherpkgs/rhels7.3/ppc64le otherpkglist=/install/custom/netboot/rhels7.3-ppc64le-netboot-service/service.rhels7.ppc64le.otherpkgs.pkglist pkgdir=/install/rhels7.3/ppc64le pkglist=/install/custom/netboot/rhels7.3-ppc64le-netboot-service/service.rhels7.ppc64le.pkglist postinstall=/install/custom/netboot/rhels7.3-ppc64le-netboot-service/service.rhels7.ppc64le.postinstall postscripts=servicenode profile=service provmethod=netboot rootimgdir=/install/custom/netboot/rhels7.3-ppc64le-netboot-service/service While you are here, if you'd like, you can do the same for your Service Node images, creating custom files and new custom osimage definitions as you need to. * Make your xCAT software available for otherpkgs processing Option 1: If you downloaded xCAT to your management node for installation, place a copy of your ``xcat-core`` and ``xcat-dep`` in your ``otherpkgdir`` directory :: lsdef -t osimage -o rhels7.3-ppc64le-netboot-service -i otherpkgdir Object name: rhels7.3-ppc64le-netboot-service otherpkgdir=/install/post/otherpkgs/rhels7.3/ppc64le cd /install/post/otherpkgs/rhels7.3/ppc64le mkdir xcat cd xcat cp -Rp /xcat-core cp -Rp /xcat-dep Option 2: If you installed your management node directly from the online repository, you will need to download the ``xcat-core`` and ``xcat-dep`` tarballs - From http://xcat.org/download.html, download the ``xcat-core`` and ``xcat-dep`` tarball files. Copy these into a subdirectory in the ``otherpkgdir`` directory. :: lsdef -t osimage -o rhels7.3-ppc64le-netboot-service -i otherpkgdir Object name: rhels7.3-ppc64le-netboot-service otherpkgdir=/install/post/otherpkgs/rhels7.3/ppc64le cd /install/post/otherpkgs/rhels7.3/ppc64le mkdir xcat cd xcat # copy the and tarballs here # extract the tarballs tar -jxvf .tar.bz2 tar -jxvf .tar.bz2 * Run image generation for your osimage definition: :: genimage rhels7.3-ppc64le-netboot-service * Prevent DHCP from starting up until xcatd has had a chance to configure it: :: export OSIMAGE_ROOT=/install/custom/netboot/rhels7.3-ppc64le-netboot-service/service chroot $OSIMAGE_ROOT/rootimg chkconfig dhcpd off chroot $OSIMAGE_ROOT/rootimg chkconfig dhcrelay off * IF using NFS hybrid mode, export /install read-only in Service Node image: :: export OSIMAGE_ROOT=/install/custom/netboot/rhels7.3-ppc64le-netboot-service/service cd $OSIMAGE_ROOT/rootimg/etc echo '/install *(ro,no_root_squash,sync,fsid=13)' >exports * Pack the image for your osimage definition: :: packimage rhels7.3-ppc64le-netboot-service Install Service Nodes ------------------------ :: rinstall service osimage=rhels7.3-ppc64le-netboot-service Watch the installation progress using either wcons or rcons: :: wcons service # make sure DISPLAY is set to your X server/VNC or rcons tail -f /var/log/messages Enable localdisk for stateless Service Node (Optional) ------------------------------------------------------ If you want, your can leverage local disk to contain some directories during the stateless nodes running. And you can customize the osimage definition to achieve it. For Service Node, it is recommended to put below directories on local disk. :: #/install (Not required when using shared /install directory) #/tftpboot (Not required when using shared /tftpboot directory) /var/log /tmp The following section explains how to accomplish this. * Change the Service Node osimage definition to enable ``localdisk`` :: #create a partition file to partition and mount the disk export OSIMAGE=rhels7.3-ppc64le-netboot-service cat< /install/custom/netboot/$OSIMAGE/partitionfile enable=yes enablepart=yes [disk] dev=/dev/sda clear=yes parts=10,50 [localspace] dev=/dev/sda2 fstype=ext4 [swapspace] dev=/dev/sda1 EOF #add the partition file to Service Node osimage definition and configure ``policy`` table chdef -t osimage -o $OSIMAGE partitionfile=/install/custom/netboot/$OSIMAGE/partitionfile chtab priority=7.1 policy.commands=getpartition policy.rule=allow #define files or directories which are required to be put on local disk #chtab litefile.image=$OSIMAGE litefile.file=/install/ litefile.options=localdisk #chtab litefile.image=$OSIMAGE litefile.file=/tftpboot/ litefile.options=localdisk chtab litefile.image=$OSIMAGE litefile.file=/var/log/ litefile.options=localdisk chtab litefile.image=$OSIMAGE litefile.file=/tmp/ litefile.options=localdisk * Run image generation and repacking for your osimage definition: :: genimage rhels7.3-ppc64le-netboot-service packimage rhels7.3-ppc64le-netboot-service .. note:: ``enablepart=yes`` in partition file will partition the local disk at every boot. If you want to preserve the contents on local disk at next boot, change to ``enablepart=no`` after the initial provision. For more information on ``localdisk`` option, refer to :ref:`setup_localdisk_label` Update Service Node Stateless Image ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ To update the xCAT software in the image at a later time: * Download the updated xcat-core and xcat-dep tarballs and place them in your osimage's otherpkgdir xcat directory as you did above. * Generate and repack the image and reboot your Service Node. * Run image generation for your osimage definition. :: genimage "" packimage "" rinstall service osimage="" .. note:: The Service Nodes are set up as NFS-root servers for the compute nodes. Any time changes are made to any compute image on the mgmt node it will be necessary to sync all changes to all Service Nodes. In our case the ``/install`` directory is mounted on the servicenodes, so the update to the compute node image is automatically available.