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layout: default
navsection: installguide
title: Install Keep-balance
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Copyright (C) The Arvados Authors. All rights reserved.
SPDX-License-Identifier: CC-BY-SA-3.0
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Keep-balance deletes unreferenced and overreplicated blocks from Keep servers, makes additional copies of underreplicated blocks, and moves blocks into optimal locations as needed (e.g., after adding new servers).
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If you are installing keep-balance on an existing system with valuable data, you can run keep-balance in "dry run" mode first and review its logs as a precaution. To do this, edit your keep-balance startup script to use the flags @-commit-pulls=false -commit-trash=false@.
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h2. Install keep-balance
Keep-balance can be installed anywhere with network access to Keep services. Typically it runs on the same host as keepproxy.
*A cluster should have only one keep-balance process running at a time.*
On Debian-based systems:
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<pre><code>~$ <span class="userinput">sudo apt-get install keep-balance</span>
</code></pre>
</notextile>
On Red Hat-based systems:
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<pre><code>~$ <span class="userinput">sudo yum install keep-balance</span>
</code></pre>
</notextile>
Verify that @keep-balance@ is functional:
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<pre><code>~$ <span class="userinput">keep-balance -h</span>
...
Usage: keep-balance [options]
Options:
-commit-pulls
send pull requests (make more replicas of blocks that are underreplicated or are not in optimal rendezvous probe order)
-commit-trash
send trash requests (delete unreferenced old blocks, and excess replicas of overreplicated blocks)
...
</code></pre>
</notextile>
h3. Create a keep-balance token
Create an Arvados superuser token for use by keep-balance.
{% include 'create_superuser_token' %}
h3. Update keepstore configuration files
On each node that runs keepstore, save the token you generated in the previous step in a text file like @/etc/arvados/keepstore/system-auth-token.txt@ and then create or update @/etc/arvados/keepstore/keepstore.yml@ with the following key:
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<pre><code>SystemAuthTokenFile: /etc/arvados/keepstore/system-auth-token.txt
</code></pre>
</notextile>
Restart all keepstore services to apply the updated configuration.
h3. Create a keep-balance configuration file
On the host running keep-balance, create @/etc/arvados/keep-balance/keep-balance.yml@ using the token you generated above. Follow this YAML format:
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<pre><code>Listen: :9005
Client:
APIHost: <span class="userinput">uuid_prefix.your.domain</span>:443
AuthToken: zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
KeepServiceTypes:
- disk
Listen: :9005
ManagementToken: <span class="userinput">xyzzy</span>
RunPeriod: 10m
CollectionBatchSize: 100000
CollectionBuffers: 1000
</code></pre>
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If your API server's SSL certificate is not signed by a recognized CA, add the @Insecure@ option to the @Client@ section:
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<pre><code>Client:
<span class="userinput">Insecure: true</span>
APIHost: ...
</code></pre>
</notextile>
h3. Start the service (option 1: systemd)
If your system does not use systemd, skip this section and follow the "runit instructions":#runit instead.
If your system uses systemd, the keep-balance service should already be set up. Start it and check its status:
<notextile>
<pre><code>~$ <span class="userinput">sudo systemctl restart keep-balance</span>
~$ <span class="userinput">sudo systemctl status keep-balance</span>
● keep-balance.service - Arvados Keep Balance
Loaded: loaded (/lib/systemd/system/keep-balance.service; enabled)
Active: active (running) since Sat 2017-02-14 18:46:01 UTC; 3 days ago
Docs: https://doc.arvados.org/
Main PID: 541 (keep-balance)
CGroup: /system.slice/keep-balance.service
└─541 /usr/bin/keep-balance -commit-pulls -commit-trash
Feb 14 18:46:01 zzzzz.arvadosapi.com keep-balance[541]: 2017/02/14 18:46:01 starting up: will scan every 10m0s and on SIGUSR1
Feb 14 18:56:01 zzzzz.arvadosapi.com keep-balance[541]: 2017/02/14 18:56:01 Run: start
Feb 14 18:56:01 zzzzz.arvadosapi.com keep-balance[541]: 2017/02/14 18:56:01 skipping zzzzz-bi6l4-rbtrws2jxul6i4t with service type "proxy"
Feb 14 18:56:01 zzzzz.arvadosapi.com keep-balance[541]: 2017/02/14 18:56:01 clearing existing trash lists, in case the new rendezvous order differs from previous run
</code></pre>
</notextile>
h3(#runit). Start the service (option 2: runit)
Install runit to supervise the keep-balance daemon. {% include 'install_runit' %}
Create a supervised service.
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<pre><code>~$ <span class="userinput">sudo mkdir /etc/service/keep-balance</span>
~$ <span class="userinput">cd /etc/service/keep-balance</span>
~$ <span class="userinput">sudo mkdir log log/main</span>
~$ <span class="userinput">printf '#!/bin/sh\nexec keep-balance -commit-pulls -commit-trash 2>&1\n' | sudo tee run</span>
~$ <span class="userinput">printf '#!/bin/sh\nexec svlogd main\n' | sudo tee log/run</span>
~$ <span class="userinput">sudo chmod +x run log/run</span>
~$ <span class="userinput">sudo sv exit .</span>
~$ <span class="userinput">cd -</span>
</code></pre>
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Use @sv stat@ and check the log file to verify the service is running.
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<pre><code>~$ <span class="userinput">sudo sv stat /etc/service/keep-balance</span>
run: /etc/service/keep-balance: (pid 12520) 2s; run: log: (pid 12519) 2s
~$ <span class="userinput">tail /etc/service/keep-balance/log/main/current</span>
2017/02/14 18:46:01 starting up: will scan every 10m0s and on SIGUSR1
2017/02/14 18:56:01 Run: start
2017/02/14 18:56:01 skipping zzzzz-bi6l4-rbtrws2jxul6i4t with service type "proxy"
2017/02/14 18:56:01 clearing existing trash lists, in case the new rendezvous order differs from previous run
</code></pre>
</notextile>
h2. Enable delete operations on keepstore volumes
Ensure your keepstore services have the "delete" operation enabled. If it is disabled (which is the default), unneeded blocks will be identified by keep-balance, but will never be deleted from the underlying storage devices.
Add the @-never-delete=false@ command line flag to your keepstore run script:
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<pre><code>keepstore <span class="userinput">-never-delete=false</span> -volume=...
</code></pre>
</notextile>
{% comment %}
// To replace the above section when the keepstore page recommends YAML...
Use the @EnableDelete@ flag in your YAML configuration file @/etc/arvados/keepstore/keepstore.yml@:
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<pre><code>...
BlobSigningKeyFile: /etc/keepstore/blob-signing.key
<span class="userinput">EnableDelete: true</span>
Listen: :25107
...
</code></pre>
</notextile>
{% endcomment %}