A rolling update will keep your cluster and all its services available on all but one node. This kind of update needs to be performed node by node. It requires that you stop all applications which use the Dolphin Express software stack (like a database server using SuperSockets) on the node you intend to update. This means your systems needs to tolerate applications going down on a single node.
Before performing a rolling update, please refer to the release notes of the new version to be installed if it supports a rolling update of the version currently installed. If this is not the case, you need to perform a complete update (see previous section).
It is possible to install the updated files while the applications are still using Dolphin Express services. However, in this case the updated Dolphin Express services will not become active until you restart them (or reboot the machine).
Perform the following steps on each node:
Log into the node and become superuser (root).
Build the new binary RPM packages for this node:
# sh DIS_install_<version>.sh --build-rpm
The created binary RPM packages will be stored in the subdirectories
frontend_RPMS which will be created in the current working directory.
To save a lot of time, you can use the binary RPM packages built on the first node that is updated on all other nodes (if they have the same CPU architecture and Linux version). Please see Section 2.3, “Installing from Binary RPMs” for more information.
# dis_services stop Stopping Dolphin SuperSockets drivers [ OK ] Stopping Dolphin SISCI driver [ OK ] Stopping Dolphin Node Manager [ OK ] Stopping Dolphin IRM driver [ OK ]
If you run sciadmin, you will notice that this node will show up as disabled (not active).
The SIA will also try to stop all services when doing an update installation. Performing this step explicitly will just assure that the services can be stopped, and that the applications are shut down properly.
If the services can not be stopped for some reason, you can still update the node, but you have to reboot it to enable the updated services. See the
--reboot option in the next step.
Run the SIA with the
<path> options to install and updated RPM packages and start the updated drivers and services. The <path> parameter to the
--use-rpms option has to point to the directory where the binary RPM packages have been built (see step 1). If you had run the SIA in
/tmp in step 1, you would issue the following command:
# sh DIS_install_<version>.sh --install-node --use-rpms /tmp
Adding the option
--reboot will reboot the node after the installation has been successful. A reboot is not required if the services were shut down successfully in step 4, but recommend to allow the low-level driver the allocation of suffcient memory resources for remote-memory access commuincation.
If the services could not be stopped in step 4, a reboot is required to allow the updated drivers to be loaded. Otherwise, the new drivers will only be installed on disk, but will not be loaded and used.
The updated services will be started by the installation and are available for use by the applications. Make sure that node has shown up as active (green) in sciadmin again before updating the next node.
If the services failed to start, a reboot of the node will fix the problem. This can be caused by situations where the memory is too fragmented for the low-level driver (see above).