Frequently Asked Questions (FAQ)

The following is a set of common questions and cross-reference pointers to the answers in the Scyld ClusterWare documentation.

Software Install/Update

How do I install or update ClusterWare RPMs?

Always use scyld-install to install or update the basic ClusterWare packages. See Installation and Upgrade of Scyld ClusterWare and Updating Base Distribution Software.

For optional ClusterWare packages that are not managed by scyld-install, see Additional Software.

Use a simple yum install or yum update to install or update non-ClusterWare base distribution packages.

How do I install or update software without head node Internet access?

See Appendix: Creating Local Repositories without Internet.

Cluster Management

What if all ``scyld-*`` commands fail?

One reason may be the root filesystem is full. See Head Node Filesystem Is 100% Full.

Another reason may be the etcd database exceeds its size limit. See etcd Database Exceeds Size Limit.

What are hardware requirements for Scyld ClusterWare?

See Required and Recommended Components.

How do I add a compute node?

See Node Creation with Known MAC address(es) or Node Creation with Unknown MAC address(es).

How do I replace a compute node?

See Replacing Failed Nodes.

How do I configure multiple head nodes?

See Managing Multiple Head Nodes.

How do I configure a job scheduler, like Slurm, TORQUE, or OpenPBS?

See Job Schedulers under Additional Software.

How do I install and configure OpenMPI?

See OpenMPI, MPICH, and/or MVAPICH under Additional Software.

How do I keep the host keys consistent across all compute nodes?

See Compute Node Host Keys.

How do I change a node name?

See Node Names and Pools.

How do I change IP addresses?

See Changing IP addresses.

Manipulating Compute Node Images

How do I create an image containing a non-default kernel?

See Modifying PXEboot Images.

How do I recreate the default image, boot config, and attributes?

See Recreating the Default Image.

How do I create an image containing a non-default base distribution?

See Appendix: Creating Arbitrary CentOS Images or Appendix: Creating Arbitrary RHEL Images.

How do I delete unused images or boot configurations to free storage space?

See Deleting Unused Images.

Issues with Interacting with Compute Nodes

What if all ``scyld-*`` commands fail?

One reason may be the etcd database exceeding its size limit. See etcd Database Exceeds Size Limit.

Why does ``scyld-nodectl -i <NODE_NAME> ssh`` fail?

Why does ``scyld-nodectl -i <NODE_NAME> shutdown`` or ``reboot`` fail?