title: Install the Crunch dispatcher
...
+{% comment %}
+Copyright (C) The Arvados Authors. All rights reserved.
+
+SPDX-License-Identifier: CC-BY-SA-3.0
+{% endcomment %}
The dispatcher normally runs on the same host/VM as the API server.
+h2. Test the Arvados job queue
+
+Crunch dispatches work from the job queue on the Arvados API server. Before you start installing the Crunch dispatcher, now's a good time to check that the API server and Git server can coordinate to create job records. Run these commands *on your shell server* to create a collection, and a job to calculate the MD5 checksum of every file in it:
+
+<notextile>
+<pre><code>~$ <span class="userinput">echo 'Hello, Crunch!' | arv-put --portable-data-hash -</span>
+…
+d40c7f35d80da669afb9db1896e760ad+49
+~$ <span class="userinput">read -rd $'\000' newjob <<EOF; arv job create --job "$newjob"
+{"script_parameters":{"input":"d40c7f35d80da669afb9db1896e760ad+49"},
+ "script_version":"0988acb472849dc0",
+ "script":"hash",
+ "repository":"arvados"}
+EOF</span>
+</code></pre>
+</notextile>
+
+If you get the error
+
+<pre>
+ArgumentError: Specified script_version does not resolve to a commit
+</pre>
+
+it often means that the API server can't read the specified repository—either because it doesn't exist, or because the user running the API server doesn't have permission to read the repository files. Check the API server's log (@/var/www/arvados-api/current/log/production.log@) for details, and double-check the instructions in the "Git server installation guide":install-arv-git-httpd.html.
+
+If everything goes well, the API server should create a job record, and your @arv@ command will output the JSON for that record. It should have state @Queued@ and script_version @0988acb472849dc08d576ee40493e70bde2132ca@. If the job JSON includes those fields, you can proceed to install the Crunch dispatcher and a compute node. This job will remain queued until you install those services.
+
h2. Perl SDK dependencies
Install the Perl SDK on the controller.
</code></pre>
</notextile>
-On Red Hat-based systems, "install SLURM and munge from source following their installation guide":https://computing.llnl.gov/linux/slurm/quickstart_admin.html.
+On Red Hat-based systems:
-Now we need to give SLURM a configuration file in @/etc/slurm-llnl/slurm.conf@. Here's an example:
+<notextile>
+<pre><code>~$ <span class="userinput">sudo yum install slurm munge slurm-munge</span>
+</code></pre>
+</notextile>
+
+Now we need to give SLURM a configuration file. On Debian-based systems, this is installed at @/etc/slurm-llnl/slurm.conf@. On Red Hat-based systems, this is installed at @/etc/slurm/slurm.conf@. Here's an example @slurm.conf@:
<notextile>
<pre>
# SCHEDULING
SchedulerType=sched/backfill
SchedulerPort=7321
-SelectType=select/cons_res
-SelectTypeParameters=CR_CPU_Memory
-FastSchedule=1
+SelectType=select/linear
+FastSchedule=0
#
# LOGGING
SlurmctldDebug=3
# COMPUTE NODES
NodeName=DEFAULT
PartitionName=DEFAULT MaxTime=INFINITE State=UP
-PartitionName=compute Default=YES Shared=yes
NodeName=compute[0-255]
-
-PartitionName=compute Nodes=compute[0-255]
+PartitionName=compute Nodes=compute[0-255] Default=YES Shared=YES
</pre>
</notextile>
-Please make sure to update the value of the @ControlMachine@ parameter to the hostname of your dispatcher (API server).
+h3. SLURM configuration essentials
-h2. Enable SLURM job dispatch
+Whenever you change this file, you will need to update the copy _on every compute node_ as well as the controller node, and then run @sudo scontrol reconfigure@.
-In your API server's @application.yml@ configuration file, add the line @crunch_job_wrapper: :slurm_immediate@ under the appropriate section. (The second colon is not a typo. It denotes a Ruby symbol.)
+*@ControlMachine@* should be a DNS name that resolves to the SLURM controller (dispatch/API server). This must resolve correctly on all SLURM worker nodes as well as the controller itself. In general SLURM is very sensitive about all of the nodes being able to communicate with the controller _and one another_, all using the same DNS names.
-h2. Crunch user account
+*@NodeName=compute[0-255]@* establishes that the hostnames of the worker nodes will be compute0, compute1, etc. through compute255.
+* There are several ways to compress sequences of names, like @compute[0-9,80,100-110]@. See the "hostlist" discussion in the @slurm.conf(5)@ and @scontrol(1)@ man pages for more information.
+* It is not necessary for all of the nodes listed here to be alive in order for SLURM to work, although you should make sure the DNS entries exist. It is easiest to define lots of hostnames up front, assigning them to real nodes and updating your DNS records as the nodes appear. This minimizes the frequency of @slurm.conf@ updates and use of @scontrol reconfigure@.
-Run @sudo adduser crunch@. The crunch user should have the same UID, GID, and home directory on all compute nodes and on the dispatcher (API server).
+Each hostname in @slurm.conf@ must also resolve correctly on all SLURM worker nodes as well as the controller itself. Furthermore, the hostnames used in the configuration file must match the hostnames reported by @hostname@ or @hostname -s@ on the nodes themselves. This applies to the ControlMachine as well as the worker nodes.
-h2. Git Repositories
+For example:
+* In @slurm.conf@ on control and worker nodes: @ControlMachine=uuid_prefix.your.domain@
+* In @slurm.conf@ on control and worker nodes: @NodeName=compute[0-255]@
+* In @/etc/resolv.conf@ on control and worker nodes: @search uuid_prefix.your.domain@
+* On the control node: @hostname@ reports @uuid_prefix.your.domain@
+* On worker node 123: @hostname@ reports @compute123.uuid_prefix.your.domain@
-Crunch scripts must be in Git repositories in the directory configured as @git_repositories_dir@/*.git (see the "API server installation":install-api-server.html#git_repositories_dir).
+h3. Automatic hostname assignment
-Once you have a repository with commits -- and you have read access to the repository -- you should be able to create a new job:
+If your worker node bootstrapping script (see "Installing a compute node":install-compute-node.html) does not send the worker's current hostname, the API server will choose an unused hostname from the set given in @application.yml@, which defaults to @compute[0-255]@.
-<pre>
-read -rd $'\000' newjob <<EOF; arv job create --job "$newjob"
-{"script_parameters":{"input":"f815ec01d5d2f11cb12874ab2ed50daa"},
- "script_version":"master",
- "script":"hash",
- "repository":"arvados"}
-EOF
-</pre>
+If it is not feasible to give your compute nodes hostnames like compute0, compute1, etc., you can accommodate other naming schemes with a bit of extra configuration.
-Without getting this error:
+If you want Arvados to assign names to your nodes with a different consecutive numeric series like @{worker1-0000, worker1-0001, worker1-0002}@, add an entry to @application.yml@; see @/var/www/arvados-api/current/config/application.default.yml@ for details. Example:
+* In @application.yml@: <code>assign_node_hostname: worker1-%<slot_number>04d</code>
+* In @slurm.conf@: <code>NodeName=worker1-[0000-0255]</code>
-<pre>
-ArgumentError: Specified script_version does not resolve to a commit
-</pre>
+If your worker hostnames are already assigned by other means, and the full set of names is known in advance, have your worker node bootstrapping script (see "Installing a compute node":install-compute-node.html) send its current hostname, rather than expect Arvados to assign one.
+* In @application.yml@: <code>assign_node_hostname: false</code>
+* In @slurm.conf@: <code>NodeName=alice,bob,clay,darlene</code>
+
+If your worker hostnames are already assigned by other means, but the full set of names is _not_ known in advance, you can use the @slurm.conf@ and @application.yml@ settings in the previous example, but you must also update @slurm.conf@ (both on the controller and on all worker nodes) and run @sudo scontrol reconfigure@ whenever a new node comes online.
+
+h2. Enable SLURM job dispatch
+
+In your API server's @application.yml@ configuration file, add the line @crunch_job_wrapper: :slurm_immediate@ under the appropriate section. (The second colon is not a typo. It denotes a Ruby symbol.)
+
+h2. Crunch user account
+
+Run @sudo adduser crunch@. The crunch user should have the same UID, GID, and home directory on all compute nodes and on the dispatcher (API server).
+
+h2. Run the Crunch dispatcher service
-h2. Running jobs
+To dispatch Arvados jobs:
-* @services/api/script/crunch-dispatch.rb@ must be running.
-* @crunch-dispatch.rb@ needs @services/crunch/crunch-job@ in its @PATH@.
+* The API server script @crunch-dispatch.rb@ must be running.
* @crunch-job@ needs the installation path of the Perl SDK in its @PERLLIB@.
-* @crunch-job@ needs the @ARVADOS_API_HOST@ (and, if necessary in a development environment, @ARVADOS_API_HOST_INSECURE@) environment variable set.
+* @crunch-job@ needs the @ARVADOS_API_HOST@ (and, if necessary, @ARVADOS_API_HOST_INSECURE@) environment variable set.
-Example @/var/service/arvados_crunch_dispatch/run@ script:
+Install runit to monitor the Crunch dispatch daemon. {% include 'install_runit' %}
-<pre>
-#!/bin/sh
+Install the script below as the run script for the Crunch dispatch service, modifying it as directed by the comments.
+
+<notextile>
+<pre><code>#!/bin/sh
set -e
rvmexec=""
-## uncomment this line if you use rvm:
-#rvmexec="/usr/local/rvm/bin/rvm-exec 2.1.1"
+## Uncomment this line if you use RVM:
+#rvmexec="/usr/local/rvm/bin/rvm-exec default"
-export PATH="$PATH":/path/to/arvados/services/crunch
-export ARVADOS_API_HOST={{ site.arvados_api_host }}
+export ARVADOS_API_HOST=<span class="userinput">uuid_prefix.your.domain</span>
export CRUNCH_DISPATCH_LOCKFILE=/var/lock/crunch-dispatch
+export HOME=$(pwd)
+export RAILS_ENV=production
-fuser -TERM -k $CRUNCH_DISPATCH_LOCKFILE || true
+## Uncomment and edit this line if your compute nodes have cgroup info
+## somewhere other than /sys/fs/cgroup (e.g., "/cgroup" for CentOS 7)
+#export CRUNCH_CGROUP_ROOT="/sys/fs/cgroup"
-## Only if your SSL cert is unverifiable:
-# export ARVADOS_API_HOST_INSECURE=yes
+## Uncomment this line if your cluster uses self-signed SSL certificates:
+#export ARVADOS_API_HOST_INSECURE=yes
-cd /path/to/arvados/services/api
-export RAILS_ENV=production
+# This is the path to docker on your compute nodes. You might need to
+# change it to "docker", "/opt/bin/docker", etc.
+export CRUNCH_JOB_DOCKER_BIN=<span class="userinput">docker.io</span>
+
+fuser -TERM -k $CRUNCH_DISPATCH_LOCKFILE || true
+cd /var/www/arvados-api/current
exec $rvmexec bundle exec ./script/crunch-dispatch.rb 2>&1
-</pre>
+</code></pre>
+</notextile>
projects / arvados.git / blobdiff