This document is an easy to follow guide to installing and running your own Electrum server on Linux. It is structured as a series of steps you need to follow, ordered in the most logical way. The next two sections describe some conventions we use in this document and hardware, software and expertise requirements.
The most up-to date version of this document is available at:
https://github.com/spesmilo/electrum-server/blob/master/HOWTO.md
In this document, lines starting with a hash sign (#) or a dollar sign (
Strings that are surrounded by "lower than" and "greater than" ( < and > ) should be replaced by the user with something appropriate. For example, should be replaced by a user chosen password. Do not confuse this notation with shell redirection ('command < file' or 'command > file')!
Lines that lack hash or dollar signs are pastes from config files. They should be copied verbatim or adapted, without the indentation tab.
apt-get install commands are suggestions for required dependencies. They conform to an Ubuntu 13.04 system but may well work with Debian or earlier and later versions of Ubuntu.
Expertise. You should be familiar with Linux command line and standard Linux commands. You should have basic understanding of git, Python packages. You should have knowledge about how to install and configure software on your Linux distribution. You should be able to add commands to your distribution's startup scripts. If one of the commands included in this document is not available or does not perform the operation described here, you are expected to fix the issue so you can continue following this howto.
Software. A recent Linux 64-bit distribution with the following software
installed: python, easy_install, git, standard C/C++
build chain. You will need root access in order to install other software or
Python libraries.
Hardware. The lightest setup is a pruning server with diskspace requirements well under 1 GB growing very moderately and less taxing on I/O and CPU once it's up and running. However note that you also need to run bitcoind and keep a copy of the full blockchain, which is roughly 9 GB in April 2013. If you have less than 2 GB of RAM make sure you limit bitcoind to 8 concurrent connections. If you have more ressources to spare you can run the server with a higher limit of historic transactions per address. CPU speed is also important, mostly for the initial block chain import, but also if you plan to run a public Electrum server, which could serve tens of concurrent requests. Any multi-core x86 CPU ~2009 or newer other than Atom should do for good performance.
This step is optional, but for better security and resource separation I
suggest you create a separate user just for running bitcoind and Electrum.
We will also use the ~/bin directory to keep locally installed files
(others might want to use /usr/local/bin instead). We will download source
code files to the ~/src directory.
# sudo adduser bitcoin --disabled-password
# su - bitcoin
$ mkdir ~/bin ~/src
$ echo $PATH
If you don't see /home/bitcoin/bin in the output, you should add this line
to your .bashrc, .profile or .bash_profile, then logout and relogin:
PATH="$HOME/bin:$PATH"
We will download the latest git snapshot for Electrum and 'install' it in our ~/bin directory:
$ mkdir -p ~/src/electrum
$ cd ~/src/electrum
$ sudo apt-get install git
$ git clone https://github.com/spesmilo/electrum-server.git server
$ chmod +x ~/src/electrum/server/server.py
$ ln -s ~/src/electrum/server/server.py ~/bin/electrum-server
In order for the latest versions of Electrum to work properly we currently recommend bitcoind 0.8.5 stable.
0.8.5 can be downloaded from github or sourceforge and it needs to be patched with an electrum specific patch.
bitcoin@master i.e. git head may not currently work with electrum-server even if the patch applies cleanly.
$ cd ~/src && wget http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.8.5/bitcoin-0.8.5-linux.tar.gz
$ tar xfz bitcoin-0.8.5-linux.tar.gz
$ cd bitcoin-0.8.5-linux/src
$ patch -p1 < ~/src/electrum/server/patch/patch
$ cd src
$ sudo apt-get install make g++ python-leveldb libboost-all-dev libssl-dev libdb++-dev
$ make USE_UPNP= -f makefile.unix
$ strip ~/src/bitcoin-0.8.5-linux/src/src/bitcoind
$ ln -s ~/src/bitcoin-0.8.5-linux/src/src/bitcoind ~/bin/bitcoind
In order to allow Electrum to "talk" to bitcoind, we need to set up a RPC
username and password for bitcoind. We will then start bitcoind and
wait for it to complete downloading the blockchain.
$ mkdir ~/.bitcoin
$ $EDITOR ~/.bitcoin/bitcoin.conf
Write this in bitcoin.conf:
rpcuser=<rpc-username>
rpcpassword=<rpc-password>
daemon=1
Restart bitcoind:
$ bitcoind
Allow some time to pass, so bitcoind connects to the network and starts
downloading blocks. You can check its progress by running:
$ bitcoind getinfo
You should also set up your system to automatically start bitcoind at boot time, running as the 'bitcoin' user. Check your system documentation to find out the best way to do this.
Electrum server depends on various standard Python libraries. These will be
already installed on your distribution, or can be installed with your
package manager. Electrum also depends on two Python libraries which we will
need to install "by hand": JSONRPClib.
$ sudo apt-get install python-setuptools
$ sudo easy_install jsonrpclib
$ sudo apt-get install python-openssl
$ sudo apt-get install python-leveldb
See the steps in README.leveldb for further details, especially if your system doesn't have the python-leveldb package.
Electrum server uses leveldb to store transactions. You can choose how many spent transactions per address you want to store on the server. The default is 100, but there are also servers with 1000 or even 10000. Few addresses have more than 10000 transactions. A limit this high can be considered to be equivalent to a "full" server. Full servers previously used abe to store the blockchain. The use of abe for electrum servers is now deprecated.
The pruning server uses leveldb and keeps a smaller and faster database by pruning spent transactions. It's a lot quicker to get up and running and requires less maintenance and diskspace than abe.
The section in the configuration file looks like this:
[leveldb]
path = /path/to/your/database
# for each address, history will be pruned if it is longer than this limit
pruning_limit = 100
As of April 2013 it takes between 6-24 hours to import 230k of blocks, depending on CPU speed, I/O speed and selected pruning limit.
It's considerably faster to index in memory. You can use /dev/shm or indexing in RAM or create a tmpfs which will also use swap if you run out of memory:
$ sudo mount -t tmpfs -o rw,nodev,nosuid,noatime,size=6000M,mode=0777 none /tmpfs
At limit 100 the database comes to 2,6 GB with 230k blocks and takes roughly 6h to import in /dev/shm. At limit 1000 the database comes to 3,0 GB with 230k blocks and takes roughly 10h to import in /dev/shm. At limit 10000 the database comes to 3,5 GB with 230k blocks and takes roughly 24h to import in /dev/shm.
Alternatively you can fetch a pre-processed leveldb from the net
You can fetch recent copies of electrum leveldb databases and further instructions from the Electrum full archival server foundry at: http://foundry.electrum.org/
To run SSL / HTTPS you need to generate a self-signed certificate using openssl. You could just comment out the SSL / HTTPS ports in the config and run without, but this is not recommended.
Use the sample code below to create a self-signed cert with a recommended validity of 5 years. You may supply any information for your sign request to identify your server. They are not currently checked by the client except for the validity date. When asked for a challenge password just leave it empty and press enter.
$ openssl genrsa -des3 -passout pass:x -out server.pass.key 2048
$ openssl rsa -passin pass:x -in server.pass.key -out server.key
writing RSA key
$ rm server.pass.key
$ openssl req -new -key server.key -out server.csr
...
Country Name (2 letter code) [AU]:US
State or Province Name (full name) [Some-State]:California
Common Name (eg, YOUR name) []: electrum-server.tld
...
A challenge password []:
...
$ openssl x509 -req -days 730 -in server.csr -signkey server.key -out server.crt
The server.crt file is your certificate suitable for the ssl_certfile= parameter and server.key corresponds to ssl_keyfile= in your electrum server config
Starting with Electrum 1.9 the client will learn and locally cache the SSL certificate for your server upon the first request to prevent man-in-the middle attacks for all further connections.
If your certificate is lost or expires on the server side you currently need to run your server with a different server name along with a new certificate for this server. Therefore it's a good idea to make an offline backup copy of your certificate and key in case you need to restore it.
Electrum reads a config file (/etc/electrum.conf) when starting up. This file includes the database setup, bitcoind RPC setup, and a few other options.
$ sudo cp ~/src/electrum/server/electrum.conf.sample /etc/electrum.conf
$ sudo $EDITOR /etc/electrum.conf
Go through the sample config options and set them to your liking. If you intend to run the server publicly have a look at README-IRC.md
Electrum server currently needs quite a few file handles to use leveldb. It also requires file handles for each connection made to the server. It's good practice to increase the open files limit to 16k. This is most easily achived by sticking the value in .bashrc of the root user who usually passes this value to all unprivileged user sessions too.
$ sudo sed -i '$a ulimit -n 16384' /root/.bashrc
We're aware the leveldb part in electrum server may leak some memory and it's good practice to to either restart the server once in a while from cron (preferred) or to at least monitor it for crashes and then restart the server. Weekly restarts should be fine for most setups. If your server gets a lot of traffic and you have a limited amount of RAM you may need to restart more often.
Two more things for you to consider:
-
To increase security you may want to close bitcoind for incoming connections and connect outbound only
-
Consider restarting bitcoind (together with electrum-server) on a weekly basis to clear out unconfirmed transactions from the local the memory pool which did not propagate over the network
The magic moment has come: you can now start your Electrum server:
$ electrum-server
You should see this on the screen:
starting Electrum server
cache: yes
If you want to stop Electrum server, open another shell and run:
$ electrum-server stop
You should also take a look at the 'start' and 'stop' scripts in
~/src/electrum/server. You can use them as a starting point to create a
init script for your system.
We will assume you have a working Electrum client, a wallet and some transactions history. You should start the client and click on the green checkmark (last button on the right of the status bar) to open the Server selection window. If your server is public, you should see it in the list and you can select it. If you server is private, you need to enter its IP or hostname and the port. Press Ok, the client will disconnect from the current server and connect to your new Electrum server. You should see your addresses and transactions history. You can see the number of blocks and response time in the Server selection window. You should send/receive some bitcoins to confirm that everything is working properly.
Say hi to the dev crew, other server operators and fans on irc.freenode.net #electrum and we'll try to congratulate you on supporting the community by running an Electrum node
If you're operating a public Electrum server please subscribe to or regulary check the following thread: https://bitcointalk.org/index.php?topic=85475.0 It'll contain announcements about important updates to Electrum server required for a smooth user experience.