Monthly Archives: June 2012

rsyncd won’t bind problem, determine what pid uses a port

We had a problem with one of our server. It’s rsyncd is not responding anymore. It’s listening to the port but it’s not accepting requests.

Here’s what the log says:

[root@SERVER ~]# tail /var/log/messages
Jun 21 13:19:46 SERVER xinetd[28270]: Swapping defaults
Jun 21 13:19:46 SERVER xinetd[28270]: readjusting service amanda
Jun 21 13:19:46 SERVER xinetd[28270]: bind failed (Address already in use (errno = 98)). service = rsync
Jun 21 13:19:46 SERVER xinetd[28270]: Service rsync failed to start and is deactivated.
Jun 21 13:19:46 SERVER xinetd[28270]: Reconfigured: new=0 old=1 dropped=0 (services)
Jun 21 13:21:34 SERVER xinetd[28270]: Exiting...
Jun 21 13:22:09 SERVER xinetd[32476]: bind failed (Address already in use (errno = 98)). service = rsync
Jun 21 13:22:09 SERVER xinetd[32476]: Service rsync failed to start and is deactivated.
Jun 21 13:22:09 SERVER xinetd[32476]: xinetd Version 2.3.14 started with libwrap loadavg labeled-networking options compiled in.
Jun 21 13:22:09 SERVER xinetd[32476]: Started working: 1 available service

We tried stopping xinetd but there is still a process bound to the 873 port:

[root@SERVER ~]# service xinetd stop
Stopping xinetd: [ OK ]
[root@SERVER ~]# telnet localhost 873
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
^]
telnet> quit
Connection closed.

If only we could determine what process is still bound to the 873 port…

Well, there’s an app for that: lsof -i tcp:<port>

[root@SERVER ~]# lsof -i tcp:873
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
rpc.statd 1963 rpcuser 7u IPv4 4798 TCP *:rsync (LISTEN)
[root@SERVER ~]# kill 1963
[root@SERVER ~]# kill 1963
-bash: kill: (1963) - No such process
[root@SERVER ~]# telnet localhost 873
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused
telnet: Unable to connect to remote host: Connection refused

Now that the process is dead, we restarted xinetd…

[root@SERVER ~]# service xinetd start
Starting xinetd: [ OK ]
[root@SERVER ~]# tail /var/log/messages
Jun 21 13:21:34 SERVER xinetd[28270]: Exiting...
Jun 21 13:22:09 SERVER xinetd[32476]: bind failed (Address already in use (errno = 98)). service = rsync
Jun 21 13:22:09 SERVER xinetd[32476]: Service rsync failed to start and is deactivated.
Jun 21 13:22:09 SERVER xinetd[32476]: xinetd Version 2.3.14 started with libwrap loadavg labeled-networking options compiled in.
Jun 21 13:22:09 SERVER xinetd[32476]: Started working: 1 available service
Jun 21 13:23:06 SERVER xinetd[32476]: Exiting...
Jun 21 13:25:18 SERVER rpc.statd[1963]: Caught signal 15, un-registering and exiting.
Jun 21 13:25:18 SERVER portmap[3556]: connect from 127.0.0.1 to unset(status): request from unprivileged port
Jun 21 13:25:31 SERVER xinetd[3912]: xinetd Version 2.3.14 started with libwrap loadavg labeled-networking options compiled in.
Jun 21 13:25:31 SERVER xinetd[3912]: Started working: 2 available services

… and that solves the problem. 🙂

References:

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Install a MySQL NDB Cluster using CentOS 6.2 with 2 MGMs/MySQL servers and 2 NDB nodes

I wrote a post few weeks back that my MySQL NDB cluster was already running. This is a follow-up post on how I did it.

Before I dug in, I read some articles first on the best practices for MySQL Cluster installations. One of the sources that I’ve read is this quite helpful presentation.

The plan was to setup the cluster with 6 components:

  • 2 Management nodes
  • 2 MySQL nodes
  • 2 NDB nodes

Based on the best practices, I only need 4 servers to accomplish this setup. With these tips in mind, this is the plan that I came up with:

  • 2 VMs (2 CPUs, 4GB RAM, 20GB drives ) – will serve as MGM nodes and MySQL servers
  • 2 Supermicro 1Us (4-core, 8GB RAM, RAID 5 of 4 140GB 10k rpm SAS) – will serve as NDB nodes
  • all servers will be installed with a minimal installation of CentOS 6.2
The servers will use these IP configuration
  • mm0 – 192.168.1.162 (MGM + MySQL)
  • mm1 – 192.168.1.211 (MGM + MySQL)
  • lbindb1 – 192.168.1.164 (NDB node)
  • lbindb2 – 192.168.1.163 (NDB node)

That’s the plan, now to execute…

I downloaded the binary packages from this mirror. If you want a different mirror, you can choose from the main download page. I only need these two:

To install the packages, I ran these commands in the respective servers

    mm0> rpm -Uhv --force MySQL-Cluster-server-gpl-7.2.5-1.el6.x86_64.rpm
    mm0> mkdir /var/lib/mysql-cluster
    mm1> rpm -Uhv --force MySQL-Cluster-server-gpl-7.2.5-1.el6.x86_64.rpm
    mm1> mkdir /var/lib/mysql-cluster
    lbindb1> rpm -Uhv --force MySQL-Cluster-server-gpl-7.2.5-1.el6.x86_64.rpm
    lbindb1> mkdir -p /var/lib/mysql-cluster/data
    lbindb2> rpm -Uhv --force MySQL-Cluster-server-gpl-7.2.5-1.el6.x86_64.rpm
    lbindb2> mkdir -p /var/lib/mysql-cluster/data

The mkdir commands will make sense in a bit…

My cluster uses these two configuration files:

  • /etc/my.cnf  – used in the NDB nodes and MySQL servers (both mm[01] and lbindb[01])
  • /var/lib/mysql-cluster/config.ini – used in the MGM nodes only (mm[01])

Contents of /etc/my.cnf:

[mysqld]
# Options for mysqld process:
ndbcluster # run NDB storage engine
ndb-connectstring=192.168.1.162,192.168.1.211 # location of management server

[mysql_cluster]
# Options for ndbd process:
ndb-connectstring=192.168.1.162,192.168.1.211 # location of management server

Contents of /var/lib/mysql-cluster/config.ini:

[ndbd default]
# Options affecting ndbd processes on all data nodes:
NoOfReplicas=2 # Setting this to 1 for now, 3 ndb nodes
DataMemory=1024M # How much memory to allocate for data storage
IndexMemory=512M
DiskPageBufferMemory=1048M
SharedGlobalMemory=384M
MaxNoOfExecutionThreads=4
RedoBuffer=32M
FragmentLogFileSize=256M
NoOfFragmentLogFiles=6

[ndb_mgmd]
# Management process options:
NodeId=1
HostName=192.168.1.162 # Hostname or IP address of MGM node
DataDir=/var/lib/mysql-cluster # Directory for MGM node log files

[ndb_mgmd]
# Management process options:
NodeId=2
HostName=192.168.1.211 # Hostname or IP address of MGM node
DataDir=/var/lib/mysql-cluster # Directory for MGM node log files

[ndbd]
# lbindb1
HostName=192.168.1.164 # Hostname or IP address
DataDir=/var/lib/mysql-cluster/data # Directory for this data node's data files

[ndbd]
# lbindb2
HostName=192.168.1.163 # Hostname or IP address
DataDir=/var/lib/mysql-cluster/data # Directory for this data node's data files

# SQL nodes
[mysqld]
HostName=192.168.1.162

[mysqld]
HostName=192.168.1.211

Once the configuration files are in place, I started the cluster with these commands (NOTE: Make sure that the firewall was properly configured first):

mm0> ndb_mgmd --ndb-nodeid=1 -f /var/lib/mysql-cluster/config.ini
mm0> service mysql start
mm1> ndb_mgmd --ndb-nodeid=2 -f /var/lib/mysql-cluster/config.ini
mm1> service mysql start
lbindb1> ndbmtd
lbindb2> ndbmtd

To verify if my cluster is really running, I logged-in into one of the MGM nodes and ran ndb_mgm like this:

I was able to set it this up a few weeks back. Unfortunately, I haven’t had the chance to really test it with our ETL scripts… I was occupied with other responsibilities…

Thinking about it now, I may have to scrap the whole cluster and install a MySQL with InnoDB + lots of RAM! hmmm… Maybe I’ll benchmark it first…

Oh well… 🙂

References: