---
layout: default
navsection: installguide
title: Install Keepstore servers
...
{% comment %}
Copyright (C) The Arvados Authors. All rights reserved.

SPDX-License-Identifier: CC-BY-SA-3.0
{% endcomment %}

Keepstore provides access to underlying storage for reading and writing content-addressed blocks, with enforcement of Arvados permissions.  Keepstore supports a variety of cloud object storage and POSIX filesystems for its backing store.

We recommend installing at least two Keepstore servers. By convention, we use the following hostname pattern:

<div class="offset1">
table(table table-bordered table-condensed).
|_Hostname_|
|keep0.@uuid_prefix@.your.domain|
|keep1.@uuid_prefix@.your.domain|
</div>

Keepstore servers should not be directly accessible from the Internet (they are accessed via "keepproxy":install-keepproxy.html), so the hostnames only need to resolve on the private network.

h2. Install Keepstore

On Debian-based systems:

<notextile>
<pre><code>~$ <span class="userinput">sudo apt-get install keepstore</span>
</code></pre>
</notextile>

On Red Hat-based systems:

<notextile>
<pre><code>~$ <span class="userinput">sudo yum install keepstore</span>
</code></pre>
</notextile>

Verify that Keepstore is functional:

<notextile>
<pre><code>~$ <span class="userinput">keepstore --version</span>
</code></pre>
</notextile>

h3. Create config file

By default, keepstore will look for its configuration file at @/etc/arvados/keepstore/keepstore.yml@

You can override the configuration file location using the @-config@ command line option to keepstore.

The following is a sample configuration file:

<pre>
# Duration for which new permission signatures (returned in PUT
# responses) will be valid.  This should be equal to the API
# server's blob_signature_ttl configuration entry.
BlobSignatureTTL: 336h0m0s

# Local file containing the secret blob signing key (used to generate
# and verify blob signatures).  The contents of the key file must be
# identical to the API server's blob_signing_key configuration entry.
BlobSigningKeyFile: ""

# Print extra debug logging
Debug: false

# Maximum number of concurrent block deletion operations (per
# volume) when emptying trash. Default is 1.
EmptyTrashWorkers: 1

# Enable trash and delete features. If false, trash lists will be
# accepted but blocks will not be trashed or deleted.
# Keepstore does not delete data on its own.  The keep-balance
# service determines which blocks are candidates for deletion
# and instructs the keepstore to move those blocks to the trash.
EnableDelete: true

# Local port to listen on. Can be 'address:port' or ':port', where
# 'address' is a host IP address or name and 'port' is a port number
# or name.
Listen: :25107

# Format of request/response and error logs: "json" or "text".
LogFormat: json
ManagementToken: ""

# Maximum RAM to use for data buffers, given in multiples of block
# size (64 MiB). When this limit is reached, HTTP requests requiring
# buffers (like GET and PUT) will wait for buffer space to be
# released.
#
# It should be set such that MaxBuffers * 64MiB + 10% fits
# comfortably in memory. On a host dedicated to running keepstore,
# divide total memory by 88MiB to suggest a suitable value. For example,
# if grep MemTotal /proc/meminfo reports MemTotal: 7125440 kB,
# compute 7125440 / (88 * 1024)=79 and configure MaxBuffers: 79
MaxBuffers: 128

# Maximum concurrent requests. When this limit is reached, new
# requests will receive 503 responses. Note: this limit does not
# include idle connections from clients using HTTP keepalive, so it
# does not strictly limit the number of concurrent connections. If
# omitted or zero, the default is 2 * MaxBuffers.
MaxRequests: 0

# Path to write PID file during startup. This file is kept open and
# locked with LOCK_EX until keepstore exits, so "fuser -k pidfile" is
# one way to shut down. Exit immediately if there is an error
# opening, locking, or writing the PID file.
PIDFile: ""

# Maximum number of concurrent pull operations. Default is 1, i.e.,
# pull lists are processed serially.
PullWorkers: 0

# Honor read requests only if a valid signature is provided.  This
# should be true, except for development use and when migrating from
# a very old version.
RequireSignatures: true

# Local file containing the Arvados API token used by keep-balance
# or data manager.  Delete, trash, and index requests are honored
# only for this token.
SystemAuthTokenFile: ""

# Path to server certificate file in X509 format. Enables TLS mode.
#
# Example: /var/lib/acme/live/keep0.example.com/fullchain
TLSCertificateFile: ""

# Path to server key file in X509 format. Enables TLS mode.
#
# The key pair is read from disk during startup, and whenever SIGHUP
# is received.
#
# Example: /var/lib/acme/live/keep0.example.com/privkey
TLSKeyFile: ""

# How often to check for (and delete) trashed blocks whose
# TrashLifetime has expired.
TrashCheckInterval: 24h0m0s

# Time duration after a block is trashed during which it can be
# recovered using an /untrash request.
TrashLifetime: 336h0m0s

# Maximum number of concurrent trash operations. Default is 1, i.e.,
# trash lists are processed serially.
TrashWorkers: 1
</pre>

h3. Notes on storage management

On its own, a keepstore server never deletes data.  The "keep-balance":install-keep-balance.html service service determines which blocks are candidates for deletion and instructs the keepstore to move those blocks to the trash.

When a block is newly written, it is protected from deletion for the duration in @BlobSignatureTTL@.  During this time, it cannot be trashed.

If keep-balance instructs keepstore to trash a block which is older than @BlobSignatureTTL@, and @EnableDelete@ is true, the block will be moved to "trash".

h3. Configure storage volumes

Available storage volume types include cloud object storage and POSIX filesystems.

If you are using S3-compatible object storage (including Amazon S3, Google Cloud Storage, and Ceph RADOS), follow the setup instructions "S3 Object Storage":configure-s3-object-storage.html page instead and then "Run keepstore as a supervised service.":#keepstoreservice

If you are using Azure Blob Storage, follow the setup instructions "Azure Blob Storage":configure-azure-blob-storage.html and then proceed to "Run keepstore as a supervised service.":#keepstoreservice

To use a POSIX filesystem, including both local filesystems (ext4, xfs) and network file system such as GPFS or Lustre, continue reading this section.

h4. Setting up filesystem mounts

Volumes are configured in the @Volumes@ section of the configuration
file.  You may provide multiple volumes for a single keepstore process
to manage multiple disks.  Keepstore distributes blocks among volumes
in round-robin fashion.

<pre>
Volumes:
- # The volume type, indicates this is a filesystem directory.
  Type: Directory

  # The actual directory that will be used as the backing store.
  Root: /mnt/local-disk

  # How much replication is performed by the underlying filesystem.
  # (for example, a network filesystem may provide its own replication).
  # This is used to inform replication decisions at the Keep layer.
  DirectoryReplication: 1

  # If true, do not accept write or trash operations, only reads.
  ReadOnly: false

  # When true, read and write operations (for whole 64MiB blocks) on
  # an individual volume will queued and issued sequentially.  When
  # false, read and write operations will be issued concurrently as
  # they come in.
  #
  # When using spinning disks where storage partitions map 1:1 to
  # physical disks that are dedicated to Keepstore, enabling this may
  # reduce contention and improve throughput by minimizing seeks.
  #
  # When using SSDs, RAID, or a parallel network filesystem, you probably
  # don't want this.
  Serialize: true

  # Storage classes to associate with this volume.  See "Configuring
  # storage classes" in the "Admin" section of doc.arvados.org.
  StorageClasses: null

  # Example of a second volume section
- DirectoryReplication: 2
  ReadOnly: false
  Root: /mnt/network-disk
  Serialize: false
  StorageClasses: null
  Type: Directory
</pre>

h3(#keepstoreservice). Run keepstore as a supervised service

Install runit to supervise the keepstore daemon.  {% include 'install_runit' %}

Install this script as the run script @/etc/sv/keepstore/run@ for the keepstore service:

<notextile>
<pre><code>#!/bin/sh

exec 2>&1
GOGC=10 exec keepstore -config /etc/arvados/keepstore/keepstore.yml
</code></pre>
</notextile>

h3. Set up additional servers

Repeat the above sections to prepare volumes and bring up supervised services on each Keepstore server you are setting up.

h3. Tell the API server about the Keepstore servers

The API server needs to be informed about the presence of your Keepstore servers. For each of the Keepstore servers you have created, please execute the following commands on your <strong>shell server</strong>.

Make sure to update the @service_host@ value to match each of your Keepstore servers.

<notextile>
<pre><code>~$ <span class="userinput">prefix=`arv --format=uuid user current | cut -d- -f1`</span>
~$ <span class="userinput">echo "Site prefix is '$prefix'"</span>
~$ <span class="userinput">read -rd $'\000' keepservice &lt;&lt;EOF; arv keep_service create --keep-service "$keepservice"</span>
<span class="userinput">{
 "service_host":"<strong>keep0.$prefix.your.domain</strong>",
 "service_port":25107,
 "service_ssl_flag":false,
 "service_type":"disk"
}
EOF</span>
</code></pre></notextile>