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Bharat Kunwar
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Merge pull request #10 from stackhpc/drain-resume
Drain/resume toggle (v0.4.0)
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‎README.md

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@@ -19,18 +19,42 @@ Role Variables
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`openhpc_packages`: additional OpenHPC packages to install
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`openhpc_enable`:
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`openhpc_enable`:
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* `control`: whether to enable control host
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* `batch`: whether to enable compute nodes
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* `batch`: whether to enable compute nodes
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* `runtime`: whether to enable OpenHPC runtime
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* `drain`: whether to drain compute nodes
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* `resume`: whether to resume compute nodes
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Example Playbook
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Example Inventory
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-----------------
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And an Ansible inventory as this:
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[openhpc_login]
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openhpc-login-0 ansible_host=10.60.253.40 ansible_user=centos
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[openhpc_compute]
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openhpc-compute-0 ansible_host=10.60.253.31 ansible_user=centos
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openhpc-compute-1 ansible_host=10.60.253.32 ansible_user=centos
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[cluster_login:children]
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openhpc_login
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[cluster_control:children]
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openhpc_login
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[cluster_batch:children]
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openhpc_compute
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Example Playbooks
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----------------
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To deploy, create a playbook which looks like this:
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---
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- hosts:
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- cluster_login
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- cluster_control
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- cluster_batch
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become: yes
@@ -53,19 +77,52 @@ To deploy, create a playbook which looks like this:
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openhpc_packages: []
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...
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Example Inventory
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-----------------
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And an Ansible inventory as this:
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[openhpc_login]
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openhpc-login-0 ansible_host=10.60.253.40 ansible_user=centos
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[openhpc_compute]
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openhpc-compute-0 ansible_host=10.60.253.33 ansible_user=centos
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To drain nodes, for example, before scaling down the cluster to 6 nodes:
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[cluster_control:children]
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openhpc_login
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---
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- hosts: openstack
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gather_facts: false
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vars:
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partition: "{{ cluster_group.output_value | selectattr('group', 'equalto', item.name) | list }}"
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openhpc_slurm_partitions:
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- name: "compute"
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flavor: "compute-A"
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image: "CentOS7.5-OpenHPC"
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num_nodes: 6
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user: "centos"
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openhpc_cluster_name: openhpc
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roles:
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# Our stackhpc.cluster-infra role can be invoked in `query` mode which
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# looks up the state of the cluster by querying the Heat API.
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- role: stackhpc.cluster-infra
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cluster_name: "{{ cluster_name }}"
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cluster_state: query
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cluster_params:
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cluster_groups: "{{ cluster_groups }}"
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tasks:
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# Given that the original cluster that was created had 8 nodes and the
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# cluster we want to create has 6 nodes, the computed desired_state
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# variable stores the list of instances to leave untouched.
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- name: Count the number of compute nodes per slurm partition
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set_fact:
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desired_state: "{{ (( partition | first).nodes | map(attribute='name') | list )[:item.num_nodes] + desired_state | default([]) }}"
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when: partition | length > 0
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with_items: "{{ openhpc_slurm_partitions }}"
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- debug: var=desired_state
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- hosts: cluster_batch
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become: yes
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vars:
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desired_state: "{{ hostvars['localhost']['desired_state'] | default([]) }}"
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roles:
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# Now, the stackhpc.openhpc role is invoked in drain/resume modes where
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# the instances in desired_state are resumed if in a drained state and
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# drained if in a resumed state.
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- role: stackhpc.openhpc
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openhpc_slurm_control_host: "{{ groups['cluster_control'] | first }}"
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openhpc_enable:
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drain: "{{ inventory_hostname not in desired_state }}"
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resume: "{{ inventory_hostname in desired_state }}"
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...
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[cluster_batch:children]
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openhpc_compute

‎defaults/main.yml

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---
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openhpc_slurm_service_enabled: true
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openhpc_slurm_service:
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openhpc_slurm_control_host:
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openhpc_slurm_control_host: "{{ inventory_hostname }}"
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openhpc_slurm_partitions: []
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openhpc_cluster_name:
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openhpc_packages: []
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openhpc_drain_timeout: 86400
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openhpc_resume_timeout: 300
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openhpc_retry_delay: 10
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openhpc_enable:
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control: false
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batch: false
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runtime: false
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drain: false
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resume: false

‎tasks/drain.yml

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---
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# Ansible tasks to drain a Slurm compute node. Waits for the compute node to be
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# drained for up to a day by default.
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#
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# Variables:
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# - node_to_drain: compute node to drain
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# - drain_timeout: seconds to wait for node to drain, default is 86400.
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- name: Get nodes in DRAINED state
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command: "sinfo --noheader --Node --format='%N' --states=DRAINED"
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register: drained_nodes_results
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changed_when: false
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- name: Drain compute node
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command: "scontrol update nodename={{ inventory_hostname }} state=DRAIN reason='maintenance'"
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when: inventory_hostname not in drained_nodes_results.stdout_lines
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- name: Check node has drained
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command: "sinfo --noheader --Node --format='%N' --states=DRAINED"
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register: drained_nodes
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until: "inventory_hostname in drained_nodes.stdout_lines"
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delay: "{{ openhpc_retry_delay }}"
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retries: "{{ (openhpc_drain_timeout/openhpc_retry_delay) | int }}"
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changed_when: false

‎tasks/main.yml

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---
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- include: control.yml
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when: openhpc_enable.control | bool
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when: openhpc_enable.control | default(false) | bool
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- include: compute.yml
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when: openhpc_enable.batch | bool
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when: openhpc_enable.batch | default(false) | bool
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- include: runtime.yml
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when: openhpc_enable.runtime | bool
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when: openhpc_enable.runtime | default(false) | bool
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- include: drain.yml
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when: openhpc_enable.drain | default(false) | bool
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delegate_to: "{{ openhpc_slurm_control_host }}"
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- include: resume.yml
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when: openhpc_enable.resume | default(false) | bool
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delegate_to: "{{ openhpc_slurm_control_host }}"
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...

‎tasks/resume.yml

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---
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# Ansible tasks to resume a Slurm compute node. Waits for the compute node to
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# change state for 5 minutes by default.
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#
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# Variables:
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# - nodes_to_resume: compute node to resume
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# - resume_timeout: seconds to wait for node to resume, default is 300.
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- name: Get nodes in ALLOC,IDLE states
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command: "sinfo --noheader --Node --format='%N' --states=ALLOC,IDLE"
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register: resumed_nodes_results
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changed_when: false
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- name: Resume compute node
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command: "scontrol update nodename={{ inventory_hostname }} state=RESUME"
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when: inventory_hostname not in resumed_nodes_results.stdout_lines
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- name: Check node has resumed
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command: "sinfo --noheader --Node --format='%N' --states=ALLOC,IDLE"
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register: resumed_nodes
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until: "inventory_hostname in resumed_nodes.stdout_lines"
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delay: "{{ openhpc_retry_delay }}"
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retries: "{{ (openhpc_resume_timeout/openhpc_retry_delay) | int }}"
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changed_when: false

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