First, "add the appropriate package repository for your distribution":{{ site.baseurl }}/install/install-manual-prerequisites.html#repos.
+{% include 'note_python27_sc' %}
+
On Debian-based systems:
<notextile>
-<pre><code>~$ <span class="userinput">sudo apt-get install perl python-virtualenv fuse python-arvados-python-client python-arvados-fuse crunchstat iptables ca-certificates</span>
+<pre><code>~$ <span class="userinput">sudo apt-get install perl python-virtualenv fuse python-arvados-python-client python-arvados-fuse crunchstat arvados-docker-cleaner iptables ca-certificates</span>
</code></pre>
</notextile>
On Red Hat-based systems:
<notextile>
-<pre><code>~$ <span class="userinput">sudo yum install perl python27-python-virtualenv fuse python27-python-arvados-python-client python27-python-arvados-fuse crunchstat iptables ca-certificates</span>
+<pre><code>~$ <span class="userinput">sudo yum install perl python27-python-virtualenv fuse python27-python-arvados-python-client python27-python-arvados-fuse crunchstat arvados-docker-cleaner iptables ca-certificates</span>
</code></pre>
</notextile>
-{% include 'note_python27_sc' %}
-
h2. Install Docker
Compute nodes must have Docker installed to run jobs inside containers. This requires a relatively recent version of Linux (at least upstream version 3.10, or a distribution version with the appropriate patches backported). Follow the "Docker Engine installation documentation":https://docs.docker.com/ for your distribution.
</pre>
</notextile>
-h2. Crunch user account
+h2. Configure the Docker cleaner
+
+The arvados-docker-cleaner program removes least recently used docker images as needed to keep disk usage below a configured limit.
+
+{% include 'notebox_begin' %}
+This also removes all containers as soon as they exit, as if they were run with `docker run --rm`. If you need to debug or inspect containers after they stop, temporarily stop arvados-docker-cleaner or run it with `--remove-stopped-containers never`.
+{% include 'notebox_end' %}
+
+On Debian-based systems, install runit:
+
+<notextile>
+<pre><code>~$ <span class="userinput">sudo apt-get install runit</span>
+</code></pre>
+</notextile>
+
+On Red Hat-based systems, "install runit from source":http://smarden.org/runit/install.html or use an alternative daemon supervisor.
+
+Configure runit to run the image cleaner using a suitable quota for your compute nodes and workload:
+
+<notextile>
+<pre><code>~$ <span class="userinput">cd /etc/sv</span>
+/etc/sv$ <span class="userinput">sudo mkdir arvados-docker-cleaner; cd arvados-docker-cleaner</span>
+/etc/sv/arvados-docker-cleaner$ <span class="userinput">sudo mkdir log log/main</span>
+/etc/sv/arvados-docker-cleaner$ <span class="userinput">sudo sh -c 'cat >log/run' <<'EOF'
+#!/bin/sh
+exec svlogd -tt main
+EOF</span>
+/etc/sv/arvados-docker-cleaner$ <span class="userinput">sudo sh -c 'cat >run' <<'EOF'
+#!/bin/sh
+exec python3 -m arvados_docker.cleaner --quota <b>50G</b>
+EOF</span>
+/etc/sv/arvados-docker-cleaner$ <span class="userinput">sudo chmod +x run log/run</span>
+</code></pre>
+</notextile>
+
+If you are using a different daemon supervisor, or if you want to test the daemon in a terminal window, an equivalent shell command to run arvados-docker-cleaner is:
+
+<notextile>
+<pre><code><span class="userinput">python3 -m arvados_docker.cleaner --quota <b>50G</b></span>
+</code></pre>
+</notextile>
+
+h2. Add a Crunch user account
Create a Crunch user account, and add it to the @fuse@ and @docker@ groups so it can use those tools: