MySQL 5.5 Release Notes
On a replication slave, you must establish a unique server ID. If this has not already been done, this part of slave setup requires a server restart.
If the slave server ID is not already set, or the current value conflicts with the value that you have chosen for the master server, you should shut down your slave server and edit the configuration to specify a unique server ID. For example:
[mysqld] server-id=2
After making the changes, restart the server.
If you are setting up multiple slaves, each one must have a
unique server-id value that
differs from that of the master and from each of the other
slaves. Think of server-id values
as something similar to IP addresses: These IDs uniquely
identify each server instance in the community of replication
partners.
Note
If you omit server-id (or set
it explicitly to its default value of 0), a slave refuses to
connect to a master.
You do not have to enable binary logging on the slave for replication to be enabled. However, if you enable binary logging on the slave, you can use the binary log for data backups and crash recovery on the slave, and also use the slave as part of a more complex replication topology (for example, where the slave acts as a master to other slaves).
# Replication
server-id=2
relay-log=mysqld-relay-bin
Maybe I'm missing something, but unless you set the log-bin=mysql-bin to the SAME value as you set in the Master Setup[1] instructions, your slave isn't really ready to become the new master when you fail-over.
At least, that's what my one experiment so far has shown.
And when I changed the log-bin on the slave to match and re-started, any queries that happened in between didn't make it back to the former-master/new-slave when I started that back up.
So I believe these Master Setup and Slave Setup should both have log-bin=xyz values that match in these docs, or leave them out and use the defaults.
But don't document one and not the other, making readers think they can change it only on the Master setup.
Please forgive me if I'm just completely off-base. Will experiment more and try to give a Beginner's Guide in a blog.
It seems like there are so many options and scenarios being documented here, that the baseline "HowTo" is obscured by the "gothcas" and "edge cases" and "if this, then that" docs...
I'm not unwilling to help, once I actually plow through it for myself :-)
1: http://dev.mysql.com/doc/refman/5.0/en/replication-howto-masterbaseconfig.html
report-host=hostname
into your my.cnf on the slave, so that the 'show slave hosts' command will work on the master.