couchdb

Data storage for all user data.

Topology

Required:

Nodes with couchdb service must also have soledad service, if email is enabled.

Suggested:

Nodes with couchdb service communicate heavily with webapp and mx.

couchdb nodes do not need to be reachable from the public internet, although the soledad service does require this.

Configuration

Nighly dumps

You can do a nightly couchdb data dump by adding this to your node config:

"couch": {
  "backup": true
}

Data will get dumped to /var/backups/couchdb.

Plain CouchDB

BigCouch is not supported on Platform version 0.8 and higher: only plain CouchDB is possible. For earlier versions, you must do this in order to use plain CouchDB:

"couch": {
  "master": true,
  "pwhash_alg": "pbkdf2"
}

Various Tasks

Re-enabling blocked account

When a user account gets destroyed from the webapp, there’s still a leftover doc in the identities db so other people can’t claim that account without an admin’s intervention. You can remove this username reservation through the webapp.

However, here is how you could do it manually, if you wanted to:

grep the identities db for the email address:

curl -s --netrc-file /etc/couchdb/couchdb.netrc -X GET http://127.0.0.1:5984/identities/_all_docs?include_docs=true|grep test_127@bitmask.net

lookup “id” and “rev” to delete the doc:

curl -s --netrc-file /etc/couchdb/couchdb.netrc -X DELETE 'http://127.0.0.1:5984/identities/b25cf10f935b58088f0d547fca823265?rev=2-715a9beba597a2ab01851676f12c3e4a'

How to find out which userstore belongs to which identity?

/usr/bin/curl -s --netrc-file /etc/couchdb/couchdb.netrc '127.0.0.1:5984/identities/_all_docs?include_docs=true' | grep testuser

{"id":"665e004870ee17aa4c94331ff3ecb173","key":"665e004870ee17aa4c94331ff3ecb173","value":{"rev":"2-2e335a75c4b79a5c2ef5c9950706fe1b"},"doc":{"_id":"665e004870ee17aa4c94331ff3ecb173","_rev":"2-2e335a75c4b79a5c2ef5c9950706fe1b","user_id":"665e004870ee17aa4c94331ff3cd59eb","address":"testuser@example.org","destination":"testuser@example.org","keys": ...

search for the “user_id” field
in this example testuser@example.org uses the database user-665e004870ee17aa4c94331ff3cd59eb

How much disk space is used by a userstore

Beware that this returns the uncompacted disk size (see http://wiki.apache.org/couchdb/Compaction)

echo "`curl --netrc -s -X GET 'http://127.0.0.1:5984/user-dcd6492d74b90967b6b874100b7dbfcf'|json_pp|grep disk_size|cut -d: -f 2`/1024"|bc

Migrating from BigCouch to plain CouchDB

At the end of this process, you will have just one node with services property equal to couchdb. If you had a BigCouch cluster before, you will be removing all but one of those machines to consolidate them into one CouchDB machine.

if you have multiple nodes with the couchdb service on them, pick one of them to be your CouchDB server, and remove the service from the others. If these machines were only doing BigCouch before, you can remove the nodes completely with leap node rm <nodename> and then you can decommission the servers
put the webapp into maintenance mode

turn off daemons that access the database. For example:

 workstation$ leap ssh <each soledad-node>
 server# /etc/init.d/soledad-server stop

 workstation$ leap ssh <mx-node>
 server# /etc/init.d/postfix stop
 server# /etc/init.d/leap-mx stop

 workstation$ leap ssh <webapp-node>
 server# /etc/init.d/nickserver stop

Alternately, you can create a temporary firewall rule to block access (run on couchdb server):

 server# iptables -A INPUT -p tcp --dport 5984 --jump REJECT

remove orphaned databases and do a backup of all remaining, active databases. This can take some time and will place several hundred megabytes of data into /var/backups/couchdb. The size and time depends on how many users there are on your system. For example, 15k users took approximately 25 minutes and 308M of space:
```
 workstation$ leap ssh <couchdb-node>
 server# cd /srv/leap/couchdb/scripts
 server# ./cleanup-user-dbs
 server# time ./couchdb_dumpall.sh
```

stop bigcouch:

 server# /etc/init.d/bigcouch stop
 server# pkill epmd

remove bigcouch:
```
 server# apt-get remove bigcouch
```
configure your couch node to use plain couchdb instead of bigcouch, you can do this by editing nodes/.json, look for this section:
```
 "couch": {
   "mode": "plain"
 }
```
change it, so it looks like this instead:
```
  "couch": {
    "mode": "plain",
    "pwhash_alg": "pbkdf2"
  }
```

restore the backup, this will take approximately the same amount of time as the backup took above:
```
 server# cd /srv/leap/couchdb/scripts
 server# time ./couchdb_restoreall.sh
```

start services again that were stopped in the beginning:

 workstation$ leap ssh soledad-nodes
 server# /etc/init.d/soledad-server start

 workstation$ leap ssh mx-node
 server# /etc/init.d/postfix start
 server# /etc/init.d/leap-mx start

 workstation$ leap ssh webapp
 server# /etc/init.d/nickserver start

Or, alternately, if you set up the firewall rule instead, now remove it:

 server# iptables -D INPUT -p tcp --dport 5984 --jump REJECT

check if everything is working, including running the test on your deployment machine:
```
 workstation$ leap test
```
Remove old bigcouch data dir /opt after you double checked everything is in place
Relax, enjoy a refreshing beverage.