Dynamically adding hosts
By default, all configuration changes made to LSF are static. To add or remove hosts within the cluster, you must manually change the configuration and restart all management candidates.
| Parameter | Configuration file | Description |
|---|---|---|
| LSF_MASTER_LIST | lsf.conf | Defines a list of management host candidates. These hosts receive information when a dynamic host is added to or removed from the cluster. Do not add dynamic hosts to this list, because dynamic hosts cannot be management hosts. |
| LSF_DYNAMIC_HOST_WAIT_TIME | lsf.conf | Defines the length of time a dynamic host waits before sending a request to the management host LIM to add the host to the cluster. |
| LSF_HOST_ADDR_RANGE | lsf.cluster.cluster_name | Identifies the range of IP addresses for hosts that can dynamically join or leave the cluster. |
Dynamic host configuration
- Management host LIM
-
The primary management host LIM runs on the management host for the cluster. The management host LIM receives requests to add hosts, and tells the management host candidates defined by the LSF_MASTER_LIST parameter to update their configuration information when a host is dynamically added or removed.
Upon startup, both static and dynamic hosts wait to receive an acknowledgment from the management host LIM. This acknowledgment indicates that the management host LIM has added the host to the cluster. Static hosts normally receive an acknowledgment because the management host LIM has access to static host information in the LSF configuration files. Dynamic hosts do not receive an acknowledgment, however, until they announce themselves to the management host LIM. The LSF_DYNAMIC_HOST_WAIT_TIME parameter in the lsf.conf file determines how long a dynamic host waits before sending a request to the management host LIM to add the host to the cluster.
- Management host candidate host LIMs
- The LSF_MASTER_LIST parameter defines the list of management host candidates.
These hosts receive updated host information from the primary management host LIM so that any
management host
candidate can take over as the primary management host for the
cluster.Important: Primary management candidate hosts should share LSF configuration and binaries.
Dynamic hosts cannot be primary management host candidates. By defining the LSF_MASTER_LIST parameter, you ensure that LSF limits the list of management host candidates to specific, static hosts.
- mbatchd
- The mbatchd daemon receives host information from the management host LIM; when it
detects the addition or removal of a dynamic host within the cluster, mbatchd
automatically reconfigures itself.Tip: After adding a host dynamically, you might have to wait for mbatchd to detect the host and reconfigure. Depending on system load, mbatchd might wait up to ten minutes before reconfiguring.
- lsadmin command
- Use the bctrld start lim command to start the LIM on a newly added dynamic host.
Allow only certain hosts to join the cluster
By default, any host can be dynamically added to the cluster. To enable security, define a value for the LSF_HOST_ADDR_RANGE parameter in the lsf.cluster.cluster_namefile to identify a range of IP addresses for hosts that are allowed to dynamically join the cluster as LSF hosts. IP addresses can have either a dotted quad notation (IPv4) or IP Next Generation (IPv6) format. You can use IPv6 addresses if you define the LSF_ENABLE_SUPPORT_IPV6 parameter in the lsf.conf file. You do not require mapping IPv4 addresses to an IPv6 format.