swift/doc/source/howto_installmultinode.rst

Instructions for a Multiple Server Swift Installation (Ubuntu)

Prerequisites

• Ubuntu Server 10.04 LTS installation media

Basic architecture and terms

• node - a host machine running one or more Swift services
• Proxy node - node that runs Proxy services; also runs TempAuth
• Storage node - node that runs Account, Container, and Object services
• ring - a set of mappings of Swift data to physical devices

This document shows a cluster using the following types of nodes:

• one Proxy node
  • Runs the swift-proxy-server processes which proxy requests to the appropriate Storage nodes. The proxy server will also contain the TempAuth service as WSGI middleware.
• five Storage nodes
  • Runs the swift-account-server, swift-container-server, and swift-object-server processes which control storage of the account databases, the container databases, as well as the actual stored objects.

Note

Fewer Storage nodes can be used initially, but a minimum of 5 is recommended for a production cluster.

This document describes each Storage node as a separate zone in the ring. It is recommended to have a minimum of 5 zones. A zone is a group of nodes that is as isolated as possible from other nodes (separate servers, network, power, even geography). The ring guarantees that every replica is stored in a separate zone. For more information about the ring and zones, see: The Rings <overview_ring>.

To increase reliability, you may want to add additional Proxy servers for performance which is described in add-proxy-server.

Network Setup Notes

This document refers to two networks. An external network for connecting to the Proxy server, and a storage network that is not accessibile from outside the cluster, to which all of the nodes are connected. All of the Swift services, as well as the rsync daemon on the Storage nodes are configured to listen on their STORAGE_LOCAL_NET IP addresses.

Note

Run all commands as the root user

General OS configuration and partitioning for each node

1. Install the baseline Ubuntu Server 10.04 LTS on all nodes.

2. Install common Swift software prereqs:

   apt-get install python-software-properties
   add-apt-repository ppa:swift-core/release
   apt-get update
   apt-get install swift python-swiftclient openssh-server

3. Create and populate configuration directories:

   mkdir -p /etc/swift
   chown -R swift:swift /etc/swift/

4. On the first node only, create /etc/swift/swift.conf:

   cat >/etc/swift/swift.conf <<EOF
   [swift-hash]
   # random unique strings that can never change (DO NOT LOSE)
   swift_hash_path_prefix = `od -t x8 -N 8 -A n </dev/random`
   swift_hash_path_suffix = `od -t x8 -N 8 -A n </dev/random`
   EOF

5. On the second and subsequent nodes: Copy that file over. It must be the same on every node in the cluster!:

   scp firstnode.example.com:/etc/swift/swift.conf /etc/swift/

6. Publish the local network IP address for use by scripts found later in this documentation:

   export STORAGE_LOCAL_NET_IP=10.1.2.3
   export PROXY_LOCAL_NET_IP=10.1.2.4

7. Create directory /var/run/swift and change the ownership to the user and group which Swift services will run under. Since the directory is only needed for runtime, when system shuts down, the directory will be gone. It is necessary to have the directory recreated when system is restarted. To do that, also add the following lines into /etc/rc.local before line "exit 0".:

   mkdir -p /var/run/swift
   chown swift:swift /var/run/swift

8. Create directory /var/cache/swift and /srv/node. Change the ownership of the directory /var/cache/swift to the user and group which Swift account, container or object services will run under. These directories are needed only for storage node (account, container or object server). The ownership of /srv/node should be root:root, this is to ensure that when storage disks unmounted unexpectedly, the objects for swift will not be created in the directory /srv/node. If you have a node only runs proxy server, you can skip this step.:

   mkdir -p /var/cache/swift /srv/node/
   chown swift:swift /var/cache/swift

Note

The random string of text in /etc/swift/swift.conf is used as a salt when hashing to determine mappings in the ring.

Configure the Proxy node

Note

It is assumed that all commands are run as the root user

1. Install swift-proxy service:

   apt-get install swift-proxy memcached

2. Create self-signed cert for SSL:

   cd /etc/swift
   openssl req -new -x509 -nodes -out cert.crt -keyout cert.key

Note

If you don't create the cert files, Swift silently uses http internally rather than https. This document assumes that you have created these certs, so if you're following along step-by-step, create them. In a production cluster, you should terminate SSL before the proxy server. SSL support is provided for testing purposes only.

1. Modify memcached to listen on the default interfaces. Preferably this should be on a local, non-public network. Edit the IP address in /etc/memcached.conf, for example:

   perl -pi -e "s/-l 127.0.0.1/-l $PROXY_LOCAL_NET_IP/" /etc/memcached.conf

2. Restart the memcached server:

   service memcached restart

3. Create /etc/swift/proxy-server.conf:

   cat >/etc/swift/proxy-server.conf <<EOF
   [DEFAULT]
   cert_file = /etc/swift/cert.crt
   key_file = /etc/swift/cert.key
   bind_port = 8080
   workers = 8
   user = swift
   
   [pipeline:main]
   pipeline = healthcheck proxy-logging cache tempauth proxy-logging proxy-server
   
   [app:proxy-server]
   use = egg:swift#proxy
   allow_account_management = true
   account_autocreate = true
   
   [filter:proxy-logging]
   use = egg:swift#proxy_logging
   
   [filter:tempauth]
   use = egg:swift#tempauth
   user_system_root = testpass .admin https://$PROXY_LOCAL_NET_IP:8080/v1/AUTH_system
   
   [filter:healthcheck]
   use = egg:swift#healthcheck
   
   [filter:cache]
   use = egg:swift#memcache
   memcache_servers = $PROXY_LOCAL_NET_IP:11211
   EOF

   Note

   If you run multiple memcache servers, put the multiple IP:port listings in the [filter:cache] section of the proxy-server.conf file like: 10.1.2.3:11211,10.1.2.4:11211. Only the proxy server uses memcache.

4. Create the account, container and object rings. The builder command is basically creating a builder file with a few parameters. The parameter with the value of 18 represents 2 ^ 18th, the value that the partition will be sized to. Set this "partition power" value based on the total amount of storage you expect your entire ring to use. The value of 3 represents the number of replicas of each object, with the last value being the number of hours to restrict moving a partition more than once.

   cd /etc/swift
   swift-ring-builder account.builder create 18 3 1
   swift-ring-builder container.builder create 18 3 1
   swift-ring-builder object.builder create 18 3 1

   Note

   For more information on building rings, see overview_ring.

5. For every storage device in /srv/node on each node add entries to each ring:

   export ZONE=                    # set the zone number for that storage device
   export STORAGE_LOCAL_NET_IP=    # and the IP address
   export WEIGHT=100               # relative weight (higher for bigger/faster disks)
   export DEVICE=sdb1
   swift-ring-builder account.builder add z$ZONE-$STORAGE_LOCAL_NET_IP:6002/$DEVICE $WEIGHT
   swift-ring-builder container.builder add z$ZONE-$STORAGE_LOCAL_NET_IP:6001/$DEVICE $WEIGHT
   swift-ring-builder object.builder add z$ZONE-$STORAGE_LOCAL_NET_IP:6000/$DEVICE $WEIGHT

   Note

   Assuming there are 5 zones with 1 node per zone, ZONE should start at 1 and increment by one for each additional node.

6. Verify the ring contents for each ring:

   swift-ring-builder account.builder
   swift-ring-builder container.builder
   swift-ring-builder object.builder

7. Rebalance the rings:

   swift-ring-builder account.builder rebalance
   swift-ring-builder container.builder rebalance
   swift-ring-builder object.builder rebalance

   Note

   Rebalancing rings can take some time.

8. Copy the account.ring.gz, container.ring.gz, and object.ring.gz files to each of the Proxy and Storage nodes in /etc/swift.

9. Make sure all the config files are owned by the swift user:

   chown -R swift:swift /etc/swift

10. Start Proxy services:

    swift-init proxy start

Configure the Storage nodes

Note

Swift should work on any modern filesystem that supports Extended Attributes (XATTRS). We currently recommend XFS as it demonstrated the best overall performance for the swift use case after considerable testing and benchmarking at Rackspace. It is also the only filesystem that has been thoroughly tested. These instructions assume that you are going to devote /dev/sdb1 to an XFS filesystem.

1. Install Storage node packages:

   apt-get install swift-account swift-container swift-object xfsprogs

2. For every device on the node, setup the XFS volume (/dev/sdb is used as an example), add mounting option inode64 when your disk is bigger than 1TB to archive a better performance.:

   fdisk /dev/sdb  (set up a single partition)
   mkfs.xfs -i size=512 /dev/sdb1
   echo "/dev/sdb1 /srv/node/sdb1 xfs noatime,nodiratime,nobarrier,logbufs=8 0 0" >> /etc/fstab
   mkdir -p /srv/node/sdb1
   mount /srv/node/sdb1
   chown swift:swift /srv/node/sdb1

3. Create /etc/rsyncd.conf:

   cat >/etc/rsyncd.conf <<EOF
   uid = swift
   gid = swift
   log file = /var/log/rsyncd.log
   pid file = /var/run/rsyncd.pid
   address = $STORAGE_LOCAL_NET_IP
   
   [account]
   max connections = 2
   path = /srv/node/
   read only = false
   lock file = /var/lock/account.lock
   
   [container]
   max connections = 2
   path = /srv/node/
   read only = false
   lock file = /var/lock/container.lock
   
   [object]
   max connections = 2
   path = /srv/node/
   read only = false
   lock file = /var/lock/object.lock
   EOF

4. Edit the RSYNC_ENABLE= line in /etc/default/rsync:

   perl -pi -e 's/RSYNC_ENABLE=false/RSYNC_ENABLE=true/' /etc/default/rsync

5. Start rsync daemon:

   service rsync start

   Note

   The rsync daemon requires no authentication, so it should be run on a local, private network.

6. Create /etc/swift/account-server.conf:

   cat >/etc/swift/account-server.conf <<EOF
   [DEFAULT]
   bind_ip = $STORAGE_LOCAL_NET_IP
   workers = 2
   
   [pipeline:main]
   pipeline = account-server
   
   [app:account-server]
   use = egg:swift#account
   
   [account-replicator]
   
   [account-auditor]
   
   [account-reaper]
   EOF

7. Create /etc/swift/container-server.conf:

   cat >/etc/swift/container-server.conf <<EOF
   [DEFAULT]
   bind_ip = $STORAGE_LOCAL_NET_IP
   workers = 2
   
   [pipeline:main]
   pipeline = container-server
   
   [app:container-server]
   use = egg:swift#container
   
   [container-replicator]
   
   [container-updater]
   
   [container-auditor]
   
   [container-sync]
   EOF

8. Create /etc/swift/object-server.conf:

   cat >/etc/swift/object-server.conf <<EOF
   [DEFAULT]
   bind_ip = $STORAGE_LOCAL_NET_IP
   workers = 2
   
   [pipeline:main]
   pipeline = object-server
   
   [app:object-server]
   use = egg:swift#object
   
   [object-replicator]
   
   [object-updater]
   
   [object-auditor]
   EOF

9. Start the storage services. If you use this command, it will try to start every service for which a configuration file exists, and throw a warning for any configuration files which don't exist:

   swift-init all start

   Or, if you want to start them one at a time, run them as below. Note that if the server program in question generates any output on its stdout or stderr, swift-init has already redirected the command's output to /dev/null. If you encounter any difficulty, stop the server and run it by hand from the command line. Any server may be started using "swift-$SERVER-$SERVICE /etc/swift/$SERVER-config", where $SERVER might be object, continer, or account, and $SERVICE might be server, replicator, updater, or auditor.

   swift-init object-server start
   swift-init object-replicator start
   swift-init object-updater start
   swift-init object-auditor start
   swift-init container-server start
   swift-init container-replicator start
   swift-init container-updater start
   swift-init container-auditor start
   swift-init account-server start
   swift-init account-replicator start
   swift-init account-auditor start

Create Swift admin account and test

You run these commands from the Proxy node.

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

   curl -k -v -H 'X-Storage-User: system:root' -H 'X-Storage-Pass: testpass' https://$PROXY_LOCAL_NET_IP:8080/auth/v1.0

2. Check that you can HEAD the account:

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

3. Check that swift works (at this point, expect zero containers, zero objects, and zero bytes):

   swift -A https://$PROXY_LOCAL_NET_IP:8080/auth/v1.0 -U system:root -K testpass stat

4. Use swift to upload a few files named 'bigfile[1-2].tgz' to a container named 'myfiles':

   swift -A https://$PROXY_LOCAL_NET_IP:8080/auth/v1.0 -U system:root -K testpass upload myfiles bigfile1.tgz
   swift -A https://$PROXY_LOCAL_NET_IP:8080/auth/v1.0 -U system:root -K testpass upload myfiles bigfile2.tgz

5. Use swift to download all files from the 'myfiles' container:

   swift -A https://$PROXY_LOCAL_NET_IP:8080/auth/v1.0 -U system:root -K testpass download myfiles

6. Use swift to save a backup of your builder files to a container named 'builders'. Very important not to lose your builders!:

   swift -A https://$PROXY_LOCAL_NET_IP:8080/auth/v1.0 -U system:root -K testpass upload builders /etc/swift/*.builder

7. Use swift to list your containers:

   swift -A https://$PROXY_LOCAL_NET_IP:8080/auth/v1.0 -U system:root -K testpass list

8. Use swift to list the contents of your 'builders' container:

   swift -A https://$PROXY_LOCAL_NET_IP:8080/auth/v1.0 -U system:root -K testpass list builders

9. Use swift to download all files from the 'builders' container:

   swift -A https://$PROXY_LOCAL_NET_IP:8080/auth/v1.0 -U system:root -K testpass download builders

Adding a Proxy Server

For reliability's sake you may want to have more than one proxy server. You can set up the additional proxy node in the same manner that you set up the first proxy node but with additional configuration steps.

Once you have more than two proxies, you also want to load balance between the two, which means your storage endpoint also changes. You can select from different strategies for load balancing. For example, you could use round robin dns, or an actual load balancer (like pound) in front of the two proxies, and point your storage url to the load balancer.

See config-proxy for the initial setup, and then follow these additional steps.

1. Update the list of memcache servers in /etc/swift/proxy-server.conf for all the added proxy servers. If you run multiple memcache servers, use this pattern for the multiple IP:port listings: 10.1.2.3:11211,10.1.2.4:11211 in each proxy server's conf file.:

   [filter:cache]
   use = egg:swift#memcache
   memcache_servers = $PROXY_LOCAL_NET_IP:11211

2. Change the storage url for any users to point to the load balanced url, rather than the first proxy server you created in /etc/swift/proxy-server.conf:

   [filter:tempauth]
   use = egg:swift#tempauth
   user_system_root = testpass .admin http[s]://<LOAD_BALANCER_HOSTNAME>:<PORT>/v1/AUTH_system

3. Next, copy all the ring information to all the nodes, including your new proxy nodes, and ensure the ring info gets to all the storage nodes as well.

4. After you sync all the nodes, make sure the admin has the keys in /etc/swift and the ownership for the ring file is correct.

Troubleshooting Notes

If you see problems, look in var/log/syslog (or messages on some distros).

Also, at Rackspace we have seen hints at drive failures by looking at error messages in /var/log/kern.log.

There are more debugging hints and tips in the admin_guide.