| Both sides previous revision
Previous revision
Next revision
|
Previous revision
|
system-wide_administration_commands_pdsh [2021/05/18 22:08]
meadline [Some Important Points about pdsh] |
system-wide_administration_commands_pdsh [2021/05/19 14:59] (current)
meadline [Some Important Points about pdsh] clarified #4 |
| |
| While ''pdsh'' is an immensely useful command, it does have some limitations and cautions. | While ''pdsh'' is an immensely useful command, it does have some limitations and cautions. |
| - ''pdsh'' only works on the headnode (login node). | |
| |
| | - The ''pdsh'' command only works from the headnode (login node) It is not available on the worker nodes. |
| - ''pdsh'' cannot be used for interactive commands (e.g. ''pdsh top'' will not work). It should be used with commands that "finish." You can break out of ''pdsh'' using multiple ''ctrl-c'' commands. | - ''pdsh'' cannot be used for interactive commands (e.g. ''pdsh top'' will not work). It should be used with commands that "finish." You can break out of ''pdsh'' using multiple ''ctrl-c'' commands. |
| |
| - If you want multiple commands to execute on the node, then the command must be surrounded by single or double quotes. For example, if the above sort command were surrounded by quotes, the sort would take place on the target nodes and not on the issuing node. The following example "sorts" on each node (there is nothing to sort) and the results are returned unordered:<code> # pdsh "uptime|sort" | - If you want multiple commands to execute on the node, then the command must be surrounded by single or double quotes. For example, if the above sort command were surrounded by quotes, the sort would take place on the target nodes and not on the issuing node. The following example "sorts" on each node (there is nothing to sort) and the results are returned unordered:<code> # pdsh "uptime|sort" |
| 0: 09:08:14 up 153 days, 18:38, 0 users, load average: 0.09, 0.08, 0.02 | n0: 09:08:14 up 153 days, 18:38, 0 users, load average: 0.09, 0.08, 0.02 |
| n2: 09:08:14 up 153 days, 18:38, 0 users, load average: 0.04, 0.05, 0.01 | n2: 09:08:14 up 153 days, 18:38, 0 users, load average: 0.04, 0.05, 0.01 |
| n1: 09:08:14 up 153 days, 18:39, 0 users, load average: 0.02, 0.04, 0.04 | n1: 09:08:14 up 153 days, 18:39, 0 users, load average: 0.02, 0.04, 0.04 |
| </code> | </code> |
| | - Although tempting, using ''pdsh'' to make permanent changes on the nodes is **not recommended**. On HPC systems, any changes will go away on the next restart of the nodes, The Warewulf Cluster toolkit provides a mechanism to globally manage all node configuration details (see [[ Warewulf Worker Node Images| VNFS images]]). \\ \\ On Data Analytics Systems (Hadoop), changing nodes by-hand may cause "node personalities" to develop (an unmanaged and unique collection of files and directories) and eventually make managing the system confusing or almost impossible. With few exceptions, full management of the Analytics systems (Hadoop) should be possible through the [[ Using the Apache Ambari Cluster Manager|Ambari Cluster Manager]]. |
| - Although tempting, using ''pdsh'' to make changes on the nodes is **not recommended**. On HPC systems, the changes will go away on the next restart of the nodes (see [[ Warewulf Worker Node Images| VNFS images]]). On Data Analytics Systems (Hadoop), changing nodes by-hand may cause "node personalities" to develop (an unmanaged and unique collection of files and directories) and eventually make managing the system confusing or almost impossible. With few exceptions, full management of the Analytics systems (Hadoop) should be possible through the [[ Using the Apache Ambari Cluster Manager|Ambari Cluster Manager]]. | |
| |
| |
