swift/doc/source/development_saio.rst

SAIO (Swift All In One)

Note

This guide assumes an existing Linux server. A physical machine or VM will work. We recommend configuring it with at least 2GB of memory and 40GB of storage space. We recommend using a VM in order to isolate Swift and its dependencies from other projects you may be working on.

Instructions for setting up a development VM

This section documents setting up a virtual machine for doing Swift development. The virtual machine will emulate running a four node Swift cluster. To begin:

• Get a Linux system server image, this guide will cover:
  • Ubuntu 14.04, 16.04 LTS
  • CentOS 7
  • Fedora
  • OpenSuse
• Create guest virtual machine from the image.

What's in a <your-user-name>

Much of the configuration described in this guide requires escalated administrator (root) privileges; however, we assume that administrator logs in as an unprivileged user and can use sudo to run privileged commands.

Swift processes also run under a separate user and group, set by configuration option, and referenced as <your-user-name>:<your-group-name>. The default user is swift, which may not exist on your system. These instructions are intended to allow a developer to use his/her username for <your-user-name>:<your-group-name>.

Note

For OpenSuse users, a user's primary group is users, so you have 2 options:

• Change ${USER}:${USER} to ${USER}:users in all references of this guide; or

• Create a group for your username and add yourself to it:

  sudo groupadd ${USER} && sudo gpasswd -a ${USER} ${USER} && newgrp ${USER}

Installing dependencies

• On apt based systems:

  sudo apt-get update
  sudo apt-get install curl gcc memcached rsync sqlite3 xfsprogs \
                       git-core libffi-dev python-setuptools \
                       liberasurecode-dev libssl-dev
  sudo apt-get install python-coverage python-dev python-nose \
                       python-xattr python-eventlet \
                       python-greenlet python-pastedeploy \
                       python-netifaces python-pip python-dnspython \
                       python-mock

• On CentOS (requires additional repositories):

  sudo yum update
  sudo yum install epel-release
  sudo yum-config-manager --enable epel extras
  sudo yum install centos-release-openstack-train
  sudo yum install curl gcc memcached rsync sqlite xfsprogs git-core \
                   libffi-devel xinetd liberasurecode-devel \
                   openssl-devel python-setuptools \
                   python-coverage python-devel python-nose \
                   pyxattr python-eventlet \
                   python-greenlet python-paste-deploy \
                   python-netifaces python-pip python-dns \
                   python-mock

• On Fedora:

  sudo dnf update
  sudo dnf install curl gcc memcached rsync-daemon sqlite xfsprogs git-core \
                   libffi-devel xinetd liberasurecode-devel \
                   openssl-devel python-setuptools \
                   python-coverage python-devel python-nose \
                   pyxattr python-eventlet \
                   python-greenlet python-paste-deploy \
                   python-netifaces python-pip python-dns \
                   python-mock

• On OpenSuse:

  sudo zypper install curl gcc memcached rsync sqlite3 xfsprogs git-core \
                      libffi-devel liberasurecode-devel python2-setuptools \
                      libopenssl-devel
  sudo zypper install python2-coverage python-devel python2-nose \
                      python-xattr python-eventlet python2-greenlet \
                      python2-netifaces python2-pip python2-dnspython \
                      python2-mock

Note

This installs necessary system dependencies and most of the python dependencies. Later in the process setuptools/distribute or pip will install and/or upgrade packages.

Configuring storage

Swift requires some space on XFS filesystems to store data and run tests.

Choose either partition-section or loopback-section.

Using a partition for storage

If you are going to use a separate partition for Swift data, be sure to add another device when creating the VM, and follow these instructions:

Note

The disk does not have to be /dev/sdb1 (for example, it could be /dev/vdb1) however the mount point should still be /mnt/sdb1.

1. Set up a single partition on the device (this will wipe the drive):

   sudo parted /dev/sdb mklabel msdos mkpart p xfs 0% 100%

2. Create an XFS file system on the partition:

   sudo mkfs.xfs /dev/sdb1

3. Find the UUID of the new partition:

   sudo blkid

4. Edit /etc/fstab and add:

   UUID="<UUID-from-output-above>" /mnt/sdb1 xfs noatime,nodiratime,logbufs=8 0 0

5. Create the Swift data mount point and test that mounting works:

   sudo mkdir /mnt/sdb1
   sudo mount -a

6. Next, skip to common-dev-section.

Using a loopback device for storage

If you want to use a loopback device instead of another partition, follow these instructions:

1. Create the file for the loopback device:

   sudo mkdir -p /srv
   sudo truncate -s 1GB /srv/swift-disk
   sudo mkfs.xfs /srv/swift-disk

   Modify size specified in the truncate command to make a larger or smaller partition as needed.

2. Edit /etc/fstab and add:

   /srv/swift-disk /mnt/sdb1 xfs loop,noatime,nodiratime,logbufs=8 0 0

3. Create the Swift data mount point and test that mounting works:

   sudo mkdir /mnt/sdb1
   sudo mount -a

Common Post-Device Setup

1. Create the individualized data links:

   sudo mkdir /mnt/sdb1/1 /mnt/sdb1/2 /mnt/sdb1/3 /mnt/sdb1/4
   sudo chown ${USER}:${USER} /mnt/sdb1/*
   for x in {1..4}; do sudo ln -s /mnt/sdb1/$x /srv/$x; done
   sudo mkdir -p /srv/1/node/sdb1 /srv/1/node/sdb5 \
                 /srv/2/node/sdb2 /srv/2/node/sdb6 \
                 /srv/3/node/sdb3 /srv/3/node/sdb7 \
                 /srv/4/node/sdb4 /srv/4/node/sdb8
   sudo mkdir -p /var/run/swift
   sudo mkdir -p /var/cache/swift /var/cache/swift2 \
                 /var/cache/swift3 /var/cache/swift4
   sudo chown -R ${USER}:${USER} /var/run/swift
   sudo chown -R ${USER}:${USER} /var/cache/swift*
   # **Make sure to include the trailing slash after /srv/$x/**
   for x in {1..4}; do sudo chown -R ${USER}:${USER} /srv/$x/; done

   Note

   We create the mount points and mount the loopback file under /mnt/sdb1. This file will contain one directory per simulated Swift node, each owned by the current Swift user.

   We then create symlinks to these directories under /srv. If the disk sdb or loopback file is unmounted, files will not be written under /srv/*, because the symbolic link destination /mnt/sdb1/* will not exist. This prevents disk sync operations from writing to the root partition in the event a drive is unmounted.

2. Restore appropriate permissions on reboot.

   • On traditional Linux systems, add the following lines to /etc/rc.local (before the exit 0):

     mkdir -p /var/cache/swift /var/cache/swift2 /var/cache/swift3 /var/cache/swift4
     chown <your-user-name>:<your-group-name> /var/cache/swift*
     mkdir -p /var/run/swift
     chown <your-user-name>:<your-group-name> /var/run/swift

   • On CentOS and Fedora we can use systemd (rc.local is deprecated):

     cat << EOF |sudo tee /etc/tmpfiles.d/swift.conf
     d /var/cache/swift 0755 ${USER} ${USER} - -
     d /var/cache/swift2 0755 ${USER} ${USER} - -
     d /var/cache/swift3 0755 ${USER} ${USER} - -
     d /var/cache/swift4 0755 ${USER} ${USER} - -
     d /var/run/swift 0755 ${USER} ${USER} - -
     EOF

   • On OpenSuse place the lines in /etc/init.d/boot.local.

   Note

   On some systems the rc file might need to be an executable shell script.

Creating an XFS tmp dir

Tests require having a directory available on an XFS filesystem. By default the tests use /tmp, however this can be pointed elsewhere with the TMPDIR environment variable.

Note

If your root filesystem is XFS, you can skip this section if /tmp is just a directory and not a mounted tmpfs. Or you could simply point to any existing directory owned by your user by specifying it with the TMPDIR environment variable.

If your root filesystem is not XFS, you should create a loopback device, format it with XFS and mount it. You can mount it over /tmp or to another location and specify it with the TMPDIR environment variable.

• Create the file for the tmp loopback device:

  sudo mkdir -p /srv
  sudo truncate -s 1GB /srv/swift-tmp  # create 1GB file for XFS in /srv
  sudo mkfs.xfs /srv/swift-tmp

• To mount the tmp loopback device at /tmp, do the following:

  sudo mount -o loop,noatime,nodiratime /srv/swift-tmp /tmp
  sudo chmod -R 1777 /tmp

  • To persist this, edit and add the following to /etc/fstab:

    /srv/swift-tmp /tmp xfs rw,noatime,nodiratime,attr2,inode64,noquota 0 0

• To mount the tmp loopback at an alternate location (for example, /mnt/tmp), do the following:

  sudo mkdir -p /mnt/tmp
  sudo mount -o loop,noatime,nodiratime /srv/swift-tmp /mnt/tmp
  sudo chown ${USER}:${USER} /mnt/tmp

  • To persist this, edit and add the following to /etc/fstab:

    /srv/swift-tmp /mnt/tmp xfs rw,noatime,nodiratime,attr2,inode64,noquota 0 0

  • Set your TMPDIR environment dir so that Swift looks in the right location:

    export TMPDIR=/mnt/tmp
    echo "export TMPDIR=/mnt/tmp" >> $HOME/.bashrc

Getting the code

1. Check out the python-swiftclient repo:

   cd $HOME; git clone https://github.com/openstack/python-swiftclient.git

2. Build a development installation of python-swiftclient:

   cd $HOME/python-swiftclient; sudo python setup.py develop; cd -

   Ubuntu 12.04 users need to install python-swiftclient's dependencies before the installation of python-swiftclient. This is due to a bug in an older version of setup tools:

   cd $HOME/python-swiftclient; sudo pip install -r requirements.txt; sudo python setup.py develop; cd -

3. Check out the Swift repo:

   git clone https://github.com/openstack/swift.git

4. Build a development installation of Swift:

   cd $HOME/swift; sudo pip install --no-binary cryptography -r requirements.txt; sudo python setup.py develop; cd -

   Note

   Due to a difference in how libssl.so is named in OpenSuse vs. other Linux distros the wheel/binary won't work; thus we use --no-binary cryptography to build cryptography locally.

   Fedora users might have to perform the following if development installation of Swift fails:

   sudo pip install -U xattr

5. Install Swift's test dependencies:

   cd $HOME/swift; sudo pip install -r test-requirements.txt

Setting up rsync

1. Create /etc/rsyncd.conf:

   sudo cp $HOME/swift/doc/saio/rsyncd.conf /etc/
   sudo sed -i "s/<your-user-name>/${USER}/" /etc/rsyncd.conf

   Here is the default rsyncd.conf file contents maintained in the repo that is copied and fixed up above:

   /../saio/rsyncd.conf

2. Enable rsync daemon

   • On Ubuntu, edit the following line in /etc/default/rsync:

     RSYNC_ENABLE=true

   Note

   You might have to create the file to perform the edits.

   • On CentOS and Fedora, enable the systemd service:

     sudo systemctl enable rsyncd

   • On OpenSuse, nothing needs to happen here.

3. On platforms with SELinux in Enforcing mode, either set to Permissive:

   sudo setenforce Permissive
   sudo sed -i 's/^SELINUX=.*/SELINUX=permissive/g' /etc/selinux/config

   Or just allow rsync full access:

   sudo setsebool -P rsync_full_access 1

4. Start the rsync daemon

   • On Ubuntu 14.04, run:

     sudo service rsync restart

   • On Ubuntu 16.04, run:

     sudo systemctl enable rsync
     sudo systemctl start rsync

   • On CentOS, Fedora and OpenSuse, run:

     sudo systemctl start rsyncd

   • On other xinetd based systems simply run:

     sudo service xinetd restart

5. Verify rsync is accepting connections for all servers:

   rsync rsync://pub@localhost/

   You should see the following output from the above command:

   account6012
   account6022
   account6032
   account6042
   container6011
   container6021
   container6031
   container6041
   object6010
   object6020
   object6030
   object6040

Starting memcached

On non-Ubuntu distros you need to ensure memcached is running:

sudo service memcached start
sudo chkconfig memcached on

or:

sudo systemctl enable memcached
sudo systemctl start memcached

The tempauth middleware stores tokens in memcached. If memcached is not running, tokens cannot be validated, and accessing Swift becomes impossible.

Optional: Setting up rsyslog for individual logging

Fedora and OpenSuse may not have rsyslog installed, in which case you will need to install it if you want to use individual logging.

1. Install rsyslogd

   • On Fedora:

     sudo dnf install rsyslog

   • On OpenSuse:

     sudo zypper install rsyslog

2. Install the Swift rsyslogd configuration:

   sudo cp $HOME/swift/doc/saio/rsyslog.d/10-swift.conf /etc/rsyslog.d/

   Be sure to review that conf file to determine if you want all the logs in one file vs. all the logs separated out, and if you want hourly logs for stats processing. For convenience, we provide its default contents below:

   /../saio/rsyslog.d/10-swift.conf

3. Edit /etc/rsyslog.conf and make the following change (usually in the "GLOBAL DIRECTIVES" section):

   $PrivDropToGroup adm

4. If using hourly logs (see above) perform:

   sudo mkdir -p /var/log/swift/hourly

   Otherwise perform:

   sudo mkdir -p /var/log/swift

5. Setup the logging directory and start syslog:

   • On Ubuntu:

     sudo chown -R syslog.adm /var/log/swift
     sudo chmod -R g+w /var/log/swift
     sudo service rsyslog restart

   • On CentOS, Fedora and OpenSuse:

     sudo chown -R root:adm /var/log/swift
     sudo chmod -R g+w /var/log/swift
     sudo systemctl restart rsyslog
     sudo systemctl enable rsyslog

Configuring each node

After performing the following steps, be sure to verify that Swift has access to resulting configuration files (sample configuration files are provided with all defaults in line-by-line comments).

1. Optionally remove an existing swift directory:

   sudo rm -rf /etc/swift

2. Populate the /etc/swift directory itself:

   cd $HOME/swift/doc; sudo cp -r saio/swift /etc/swift; cd -
   sudo chown -R ${USER}:${USER} /etc/swift

3. Update <your-user-name> references in the Swift config files:

   find /etc/swift/ -name \*.conf | xargs sudo sed -i "s/<your-user-name>/${USER}/"

The contents of the configuration files provided by executing the above commands are as follows:

1. /etc/swift/swift.conf

   /../saio/swift/swift.conf

2. /etc/swift/proxy-server.conf

   /../saio/swift/proxy-server.conf

3. /etc/swift/object-expirer.conf

   /../saio/swift/object-expirer.conf

4. /etc/swift/container-reconciler.conf

   /../saio/swift/container-reconciler.conf

5. /etc/swift/container-sync-realms.conf

   /../saio/swift/container-sync-realms.conf

6. /etc/swift/account-server/1.conf

   /../saio/swift/account-server/1.conf

7. /etc/swift/container-server/1.conf

   /../saio/swift/container-server/1.conf

8. /etc/swift/object-server/1.conf

   /../saio/swift/object-server/1.conf

9. /etc/swift/account-server/2.conf

   /../saio/swift/account-server/2.conf

10. /etc/swift/container-server/2.conf

    /../saio/swift/container-server/2.conf

11. /etc/swift/object-server/2.conf

    /../saio/swift/object-server/2.conf

12. /etc/swift/account-server/3.conf

    /../saio/swift/account-server/3.conf

13. /etc/swift/container-server/3.conf

    /../saio/swift/container-server/3.conf

14. /etc/swift/object-server/3.conf

    /../saio/swift/object-server/3.conf

15. /etc/swift/account-server/4.conf

    /../saio/swift/account-server/4.conf

16. /etc/swift/container-server/4.conf

    /../saio/swift/container-server/4.conf

17. /etc/swift/object-server/4.conf

    /../saio/swift/object-server/4.conf

Setting up scripts for running Swift

1. Copy the SAIO scripts for resetting the environment:

   mkdir -p $HOME/bin
   cd $HOME/swift/doc; cp saio/bin/* $HOME/bin; cd -
   chmod +x $HOME/bin/*

2. Edit the $HOME/bin/resetswift script

   The template resetswift script looks like the following:

   /../saio/bin/resetswift

   If you did not set up rsyslog for individual logging, remove the find /var/log/swift... line:

   sed -i "/find \/var\/log\/swift/d" $HOME/bin/resetswift

3. Install the sample configuration file for running tests:

   cp $HOME/swift/test/sample.conf /etc/swift/test.conf

   The template test.conf looks like the following:

   /../../test/sample.conf

Configure environment variables for Swift

1. Add an environment variable for running tests below:

   echo "export SWIFT_TEST_CONFIG_FILE=/etc/swift/test.conf" >> $HOME/.bashrc

2. Be sure that your PATH includes the bin directory:

   echo "export PATH=${PATH}:$HOME/bin" >> $HOME/.bashrc

3. If you are using a loopback device for Swift Storage, add an environment var to substitute /dev/sdb1 with /srv/swift-disk:

   echo "export SAIO_BLOCK_DEVICE=/srv/swift-disk" >> $HOME/.bashrc

4. If you are using a device other than /dev/sdb1 for Swift storage (for example, /dev/vdb1), add an environment var to substitute it:

   echo "export SAIO_BLOCK_DEVICE=/dev/vdb1" >> $HOME/.bashrc

5. If you are using a location other than /tmp for Swift tmp data (for example, /mnt/tmp), add TMPDIR environment var to set it:

   export TMPDIR=/mnt/tmp
   echo "export TMPDIR=/mnt/tmp" >> $HOME/.bashrc

6. Source the above environment variables into your current environment:

   . $HOME/.bashrc

Constructing initial rings

1. Construct the initial rings using the provided script:

   remakerings

   The remakerings script looks like the following:

   /../saio/bin/remakerings

   You can expect the output from this command to produce the following. Note that 3 object rings are created in order to test storage policies and EC in the SAIO environment. The EC ring is the only one with all 8 devices. There are also two replication rings, one for 3x replication and another for 2x replication, but those rings only use 4 devices:

   Device d0r1z1-127.0.0.1:6010R127.0.0.1:6010/sdb1_"" with 1.0 weight got id 0
   Device d1r1z2-127.0.0.2:6020R127.0.0.2:6020/sdb2_"" with 1.0 weight got id 1
   Device d2r1z3-127.0.0.3:6030R127.0.0.3:6030/sdb3_"" with 1.0 weight got id 2
   Device d3r1z4-127.0.0.4:6040R127.0.0.4:6040/sdb4_"" with 1.0 weight got id 3
   Reassigned 3072 (300.00%) partitions. Balance is now 0.00.  Dispersion is now 0.00
   Device d0r1z1-127.0.0.1:6010R127.0.0.1:6010/sdb1_"" with 1.0 weight got id 0
   Device d1r1z2-127.0.0.2:6020R127.0.0.2:6020/sdb2_"" with 1.0 weight got id 1
   Device d2r1z3-127.0.0.3:6030R127.0.0.3:6030/sdb3_"" with 1.0 weight got id 2
   Device d3r1z4-127.0.0.4:6040R127.0.0.4:6040/sdb4_"" with 1.0 weight got id 3
   Reassigned 2048 (200.00%) partitions. Balance is now 0.00.  Dispersion is now 0.00
   Device d0r1z1-127.0.0.1:6010R127.0.0.1:6010/sdb1_"" with 1.0 weight got id 0
   Device d1r1z1-127.0.0.1:6010R127.0.0.1:6010/sdb5_"" with 1.0 weight got id 1
   Device d2r1z2-127.0.0.2:6020R127.0.0.2:6020/sdb2_"" with 1.0 weight got id 2
   Device d3r1z2-127.0.0.2:6020R127.0.0.2:6020/sdb6_"" with 1.0 weight got id 3
   Device d4r1z3-127.0.0.3:6030R127.0.0.3:6030/sdb3_"" with 1.0 weight got id 4
   Device d5r1z3-127.0.0.3:6030R127.0.0.3:6030/sdb7_"" with 1.0 weight got id 5
   Device d6r1z4-127.0.0.4:6040R127.0.0.4:6040/sdb4_"" with 1.0 weight got id 6
   Device d7r1z4-127.0.0.4:6040R127.0.0.4:6040/sdb8_"" with 1.0 weight got id 7
   Reassigned 6144 (600.00%) partitions. Balance is now 0.00.  Dispersion is now 0.00
   Device d0r1z1-127.0.0.1:6011R127.0.0.1:6011/sdb1_"" with 1.0 weight got id 0
   Device d1r1z2-127.0.0.2:6021R127.0.0.2:6021/sdb2_"" with 1.0 weight got id 1
   Device d2r1z3-127.0.0.3:6031R127.0.0.3:6031/sdb3_"" with 1.0 weight got id 2
   Device d3r1z4-127.0.0.4:6041R127.0.0.4:6041/sdb4_"" with 1.0 weight got id 3
   Reassigned 3072 (300.00%) partitions. Balance is now 0.00.  Dispersion is now 0.00
   Device d0r1z1-127.0.0.1:6012R127.0.0.1:6012/sdb1_"" with 1.0 weight got id 0
   Device d1r1z2-127.0.0.2:6022R127.0.0.2:6022/sdb2_"" with 1.0 weight got id 1
   Device d2r1z3-127.0.0.3:6032R127.0.0.3:6032/sdb3_"" with 1.0 weight got id 2
   Device d3r1z4-127.0.0.4:6042R127.0.0.4:6042/sdb4_"" with 1.0 weight got id 3
   Reassigned 3072 (300.00%) partitions. Balance is now 0.00.  Dispersion is now 0.00

2. Read more about Storage Policies and your SAIO policies_saio

Testing Swift

1. Verify the unit tests run:

   $HOME/swift/.unittests

   Note that the unit tests do not require any Swift daemons running.

2. Start the "main" Swift daemon processes (proxy, account, container, and object):

   startmain

   (The "Unable to increase file descriptor limit. Running as non-root?" warnings are expected and ok.)

   The startmain script looks like the following:

   /../saio/bin/startmain

3. Get an X-Storage-Url and X-Auth-Token:

   curl -v -H 'X-Storage-User: test:tester' -H 'X-Storage-Pass: testing' http://127.0.0.1:8080/auth/v1.0

4. Check that you can GET account:

   curl -v -H 'X-Auth-Token: <token-from-x-auth-token-above>' <url-from-x-storage-url-above>

5. Check that swift command provided by the python-swiftclient package works:

   swift -A http://127.0.0.1:8080/auth/v1.0 -U test:tester -K testing stat

6. Verify the functional tests run:

   $HOME/swift/.functests

   (Note: functional tests will first delete everything in the configured accounts.)

7. Verify the probe tests run:

   $HOME/swift/.probetests

   (Note: probe tests will reset your environment as they call resetswift for each test.)

Debugging Issues

If all doesn't go as planned, and tests fail, or you can't auth, or something doesn't work, here are some good starting places to look for issues:

1. Everything is logged using system facilities -- usually in /var/log/syslog, but possibly in /var/log/messages on e.g. Fedora -- so that is a good first place to look for errors (most likely python tracebacks).
2. Make sure all of the server processes are running. For the base functionality, the Proxy, Account, Container, and Object servers should be running.
3. If one of the servers are not running, and no errors are logged to syslog, it may be useful to try to start the server manually, for example: swift-object-server /etc/swift/object-server/1.conf will start the object server. If there are problems not showing up in syslog, then you will likely see the traceback on startup.
4. If you need to, you can turn off syslog for unit tests. This can be useful for environments where /dev/log is unavailable, or which cannot rate limit (unit tests generate a lot of logs very quickly). Open the file SWIFT_TEST_CONFIG_FILE points to, and change the value of fake_syslog to True.
5. If you encounter a 401 Unauthorized when following Step 12 where you check that you can GET account, use sudo service memcached status and check if memcache is running. If memcache is not running, start it using sudo service memcached start. Once memcache is running, rerun GET account.

Known Issues

Listed here are some "gotcha's" that you may run into when using or testing your SAIO:

1. fallocate_reserve - in most cases a SAIO doesn't have a very large XFS partition so having fallocate enabled and fallocate_reserve set can cause issues, specifically when trying to run the functional tests. For this reason fallocate has been turned off on the object-servers in the SAIO. If you want to play with the fallocate_reserve settings then know that functional tests will fail unless you change the max_file_size constraint to something more reasonable then the default (5G). Ideally you'd make it 1/4 of your XFS file system size so the tests can pass.