@title = "couchdb"
@summary = "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


Deprecated BigCouch Tasks
-----------------------------------------

As of release 0.8, the LEAP platform no longer supports BigCouch. This information is kept here for historical reference.

### Rebalance Cluster

Bigcouch currently does not have automatic rebalancing.
It will probably be added after merging into couchdb.
If you add a node, or remove one node from the cluster,

1. make sure you have a backup of all DBs !

1. put the webapp into [[maintenance mode => services/webapp#maintenance-mode]]

1. Stop all services that access the database:

    ```
    workstation$ leap ssh soledad-nodes
    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
    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
    ```

1. dump the dbs:

    ```
    cd /srv/leap/couchdb/scripts
    time ./couchdb_dumpall.sh
    ```

1. delete all dbs

1. shut down old node

1. check the couchdb members

    ```
    curl -s —netrc-file /etc/couchdb/couchdb.netrc -X GET http://127.0.0.1:5986/nodes/_all_docs
    curl -s —netrc-file /etc/couchdb/couchdb.netrc http://127.0.0.1:5984/_membership
    ```

1. remove bigcouch from all nodes

    ```
    apt-get --purge remove bigcouch
    ```

1. deploy to all couch nodes

    ```
    leap deploy couchdb
    ```

1. most likely, deploy will fail because bigcouch will complain about not all nodes beeing connected. Let the deploy finish, restart the bigcouch service on all nodes and re-deploy:

    ```
    /etc/init.d/bigcouch restart
    ```

1. restore the backup

    ```
    cd /srv/leap/couchdb/scripts
    time ./couchdb_restoreall.sh
    ```

### Migrating from BigCouch to plain CouchDB

Here are the steps needed to replace BigCouch with CouchDB.

At the end of this process, you will have just *one* noe 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.

1. 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 couchdb, you can remove the nodes completely with `leap node rm <nodename>` and then you can decommission the servers

1. put the webapp into [[maintenance mode => webapp#maintenance-mode]]

1. turn off daemons that access the database. For example:

    ```
    workstation$ leap ssh soledad-nodes
    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
    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
    ```

1. 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:

    ```
    server# cd /srv/leap/couchdb/scripts
    server# ./cleanup-user-dbs
    server# time ./couchdb_dumpall.sh
    ```

1. stop bigcouch:

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

1. remove bigcouch:

    ```
    server# apt-get remove bigcouch
    ```

1. configure your couch node to use plain couchdb instead of bigcouch. See section "Use plain couchdb instead of bigcouch" below for details.

1. deploy to the couch node:

    ```
    workstation$ leap deploy couchdb
    ```

    If you used the iptables method of blocking access to couchdb, you need to run it again because the deploy just overwrote all the iptables rules:

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

1. 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
    ```

1. 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
    ```

1. check if everything is working, including running the test on your deployment machine:

    ```
    workstation$ leap test
    ```

1. Remove old bigcouch data dir `/opt` after you double checked everything is in place

1. Relax, enjoy a refreshing beverage.