Instantiate or restore a virtual cluster (interactive mode)¶
Synopsis¶
pcocc alloc [OPTIONS] [BATCH_OPTIONS]... CLUSTER_DEFINITION
Descrition¶
Instantiate or restore a virtual cluster in interactive mode. A cluster definition is expressed as a list of templates and counts. For example, pcocc alloc tpl1:6,tpl2:2 instantiates a cluster with 6 VMs from template tpl1 and 2 VMs from template tpl2.
By default, an interactive shell is launched which allows to easily interact with the virtual cluster as all pcocc commands launched from the shell implicitly target the related virtual cluster. Resources are relinquished when either the VMs are powered off or the interactive shell exits (see below). Any data stored on ephemeral disks is lost after the allocation completes.
Batch options are passed on to the underlying batch manager (see salloc(1)). By default allocations are created with the name pcocc unless specified otherwise in the batch options. From outside the interactive shell, pcocc commands look for a job named pcocc and will target it if there is only one match. Otherwise, the id or name of the allocation hosting the cluster must be specified.
Instead of launching an interactive shell, it is possible to execute a script on the front-end node with the -E option. The cluster will be terminated once the script exits. As in the in interactive shell, pcocc commands launched within the script implicitely target the current cluster.
Options¶
- -r, --restart-ckpt [DIR]
- Restart cluster from the specified checkpoint
- -E, --alloc-script [SCRIPT]
- Execute a script on the allocation node
- -h, --help
- Show this message and exit.
Examples¶
Instanciate a new virtual cluster¶
To allocate eight VMs with four cores each with the test SLURM qos, six from template tpl1 and two from tpl2:
pcocc alloc -c 4 --qos=test -J ubuntu tpl1:6,tpl2:2
Restore a checkpointed cluster¶
The pcocc-ckpt(1) command allows to save the state of a whole cluster (disks and memory) in a checkpoint. Assuming a cluster was submitted and checkpointed as follows:
pcocc alloc -c 8 myubuntu:3
pcocc ckpt ./savedalloc
To restore it from the checkpoint in interactive mode:
pcocc alloc -c 8 -r $PWD/savedalloc myubuntu:3
Warning
- Make sure that the parameters in the restore command (core count, template types, ...) are the same that were used when the cluster was first allocated. The cluster also has to be restored on the same model of physical nodes as when it was first allocated.
- The restore path must be an absolute path