We can control the CPU frequency with the cpufrequtils package. Installation is quite easy.
$ sudo aptitude install cpufrequtils
To check to see if it’s installed.
[06:41:32] xavi@debian: ~ $ lsmod | grep -i cpu acpi_cpufreq 6796 1 cpufreq_powersave 1856 0 cpufreq_stats 3776 0 cpufreq_ondemand 6476 1 freq_table 4224 3 acpi_cpufreq,cpufreq_stats,cpufreq_ondemand cpufreq_userspace 3172 0 cpufreq_conservative 5960 0 processor 32576 4 acpi_cpufreq,thermal [06:45:26] xavi@debian: ~ $
Here is another Perl script. This one given an Apache log file will tell you the number of hits per IP. Here is the code.
#!/usr/bin/perl -w
use strict;
use diagnostics;
if( $#ARGV != 0 ){
print "Usage: ./parser.pl <logfile>\n";
exit 1; }
# Opening logfile
open FILE, "$ARGV[0]" or die $!;
# Defining variables
my @lines = <FILE>;
my @ip;
my $items = scalar(@lines);
my ($i, $value);
my %hits;
# Removing IP addresses from logfile and counting the hits per IP.
for ($i = 0; $i < $items; $i++)
{ @ip = split (/ /, $lines[$i]);
if (exists $hits{$ip[0]}) {
$hits{$ip[0]} = $hits{$ip[0]}+1;
chomp($hits{$ip[0]}); }
else { $hits{$ip[0]} = 1; }
}
# Ordering and printing the hits per IP.
foreach $value (sort {"$hits{$b}" <=> "$hits{$a}" } keys %hits)
{ print "$value made $hits{$value} hits.\n"; }
Here is an usage example.
xavi@debianserver:~/Perl$ ./parser.pl /tmp/apachelog 12.130.86.9 made 106 hits. 208.111.39.192 made 89 hits. 67.195.114.231 made 42 hits. 98.14.22.97 made 27 hits. 208.54.45.78 made 17 hits. 213.5.71.12 made 16 hits. 199.106.237.37 made 15 hits. 66.249.67.212 made 15 hits. 208.54.45.62 made 12 hits. 87.250.252.242 made 9 hits. 174.121.74.234 made 6 hits. 188.187.102.74 made 6 hits. 208.54.45.72 made 5 hits. 64.40.121.184 made 4 hits. 206.196.125.114 made 3 hits. 207.46.13.94 made 2 hits. 220.181.146.169 made 2 hits. 142.166.170.101 made 2 hits. 220.181.94.225 made 2 hits. 142.166.170.100 made 2 hits. 65.52.108.60 made 2 hits. 207.46.199.182 made 2 hits. 207.46.13.101 made 2 hits. 208.54.45.56 made 2 hits. 209.2.233.223 made 1 hits. 67.210.218.102 made 1 hits. 66.249.67.66 made 1 hits. 220.181.7.54 made 1 hits. 207.46.199.199 made 1 hits.
As usual, suggestions are always welcome.
I don’t feel like doing a long post today so I’ll do some basic MySQL. First lets change the MySQL prompt. Here is a default MySQL prompt.
mysql> use test; Database changed mysql> select now(); +---------------------+ | now() | +---------------------+ | 2010-08-17 06:41:00 | +---------------------+ 1 row in set (0.00 sec) mysql>
Pretty boring, right? Lets spice this a little bit. Type prompt mysql \u@\d> from the MySQL prompt and lets see what happens.
mysql> prompt mysql \u@\d> PROMPT set to 'mysql \u@\d>' mysql root@test> select now() \G *************************** 1. row *************************** now(): 2010-08-17 06:44:56 1 row in set (0.00 sec) mysql root@test>
What we just did is modify the MySQL prompt to show us the user and the database being used. This is much more informative than the previous MySQL prompt.
Now what if we wanted to know the uptime of the database. Pretty simple type status; and that will give us the time the database has been up.
mysql root@test>status; -------------- mysql Ver 14.12 Distrib 5.0.75, for debian-linux-gnu (i486) using readline 5.2 Connection id: 39 Current database: test Current user: root@localhost SSL: Not in use Current pager: stdout Using outfile: '' Using delimiter: ; Server version: 5.0.75-0ubuntu10.5-log (Ubuntu) Protocol version: 10 Connection: Localhost via UNIX socket Server characterset: latin1 Db characterset: latin1 Client characterset: latin1 Conn. characterset: latin1 UNIX socket: /var/run/mysqld/mysqld.sock Uptime: 10 min 54 sec Threads: 1 Questions: 125 Slow queries: 0 Opens: 34 Flush tables: 1 Open tables: 28 Queries per second avg: 0.191 -------------- mysql root@test>
If we wanted to know the running processes just type: show full processlist \G.
mysql root@test>show full processlist \G
*************************** 1. row ***************************
Id: 39
User: root
Host: localhost
db: test
Command: Query
Time: 0
State: NULL
Info: show full processlist
1 row in set (0.00 sec)
mysql root@test>
This is all. I know this is very simple stuff, but didn’t felt like doing a long and complex post. As usual suggestions are always welcome.
References:
Let’s get started with another Tomcat chapter in this blog. Tomcat comes by default with the UserDatabaseRealm which is really crappy because it reads user info from tomcat-users.xml file and a Tomcat restart is needed for the changes to take effect. This is not appropriate for a production environment so we are going to authenticate against a MySQL database instead of the tomcat-users.xml file.
Continue reading
Let’s say you want to have two Tomcat JVMs running. How do we do it? It’s quite easy. We only need to copy some directories and modify the ports were we want Tomcat to run. We previously showed how to install Tomcat. Lets create the directory where we will make the new JVM run.
tomcat@debian:~$ mkdir /opt/tomcat/srva tomcat@debian:~$
Now we copy the webapps, conf and bin directories to /opt/tomcat/srva and create some directories in /opt/tomcat/srva.
tomcat@debian:/opt/tomcat$ cp -R webapps/ /opt/tomcat/srva/ tomcat@debian:/opt/tomcat$ cp -R conf/ /opt/tomcat/srva/ tomcat@debian:/opt/tomcat$ cp -R bin/ /opt/tomcat/srva/ tomcat@debian:/opt/tomcat$ mkdir srva/logs srva/temp srva/shared srva/common srva/work
We are now going to change startup ports to 8081 instead of default 8080 in /opt/tomcat/conf/server.xml. Don’t forget the shutdown port too.
tomcat@debian:/opt/tomcat$ grep -i port srva/conf/server.xml
<Server port="8006" shutdown="SHUTDOWN">
<!-- JMX Support for the Tomcat server. Documentation at /docs/non-existent.html -->
Define a non-SSL HTTP/1.1 Connector on port 8080
<Connector port="8081" protocol="HTTP/1.1"
redirectPort="8444" />
port="8080" protocol="HTTP/1.1"
redirectPort="8443" />
<!-- Define a SSL HTTP/1.1 Connector on port 8443
<Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true"
<!-- Define an AJP 1.3 Connector on port 8009 -->
<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />
<!-- You should set jvmRoute to support load-balancing via AJP ie :
tomcat@debian:/opt/tomcat$
Now we need to define $CATALINA_BASE and $CATALINA_HOME. The way I did is by adding them to startup.sh in the srva/bin directory. Add the following to startup.sh.
CATALINA_HOME="/opt/tomcat/" export CATALINA_HOME CATALINA_BASE="/opt/tomcat/srva" export CATALINA_BASE JAVA_HOME="/opt/java" export JAVA_HOME
We should now be ready to go. So lets get the party started.
tomcat@debian:/opt/tomcat$ echo "starting orig instance"; bin/startup.sh; echo "starting srva new instance"; srva/bin/startup.sh starting orig instance Using CATALINA_BASE: /opt/tomcat Using CATALINA_HOME: /opt/tomcat Using CATALINA_TMPDIR: /opt/tomcat/temp Using JRE_HOME: /opt/java Using CLASSPATH: /opt/tomcat/bin/bootstrap.jar starting srva new instance Using CATALINA_BASE: /opt/tomcat/srva Using CATALINA_HOME: /opt/tomcat/ Using CATALINA_TMPDIR: /opt/tomcat/srva/temp Using JRE_HOME: /opt/java Using CLASSPATH: /opt/tomcat/srva/bin/tomcat-juli.jar:/opt/tomcat//bin/bootstrap.jar tomcat@debian:/opt/tomcat$ ps auxwww | grep -i java | grep -v grep tomcat 4759 10.4 1.3 1065228 50128 pts/0 Sl 12:37 0:03 /opt/java/bin/java -Djava.util.logging.config.file=/opt/tomcat /conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/opt/tomcat/endorsed -classpath /opt/tomcat/bin/bootstrap.jar -Dcatalina.base=/opt/tomcat -Dcatalina.home=/opt/tomcat -Djava.io.tmpdir=/opt/tomcat/temp org.apache.catalina.startup.Bootstrap start tomcat 4769 10.4 1.3 1064652 47872 pts/0 Sl 12:37 0:03 /opt/java/bin/java -Djava.util.logging.config.file=/opt/tomcat/srva/conf /logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/opt/tomcat//endorsed -classpath /opt/tomcat/srva/bin/tomcat-juli.jar:/opt/tomcat//bin/bootstrap.jar -Dcatalina.base=/opt/tomcat/srva -Dcatalina.home=/opt /tomcat/ -Djava.io.tmpdir=/opt/tomcat/srva/temp org.apache.catalina.startup.Bootstrap start tomcat@debian:/opt/tomcat$
We see from the ps output that there are two java processes running. So lets check on what ports they are running. They should be on 8080 and 8081.
tomcat@debian:/opt/tomcat$ lsof -i :8080 COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME java 4759 tomcat 28u IPv6 20974 TCP *:http-alt (LISTEN) tomcat@debian:/opt/tomcat$ lsof -i :8081 COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME java 4769 tomcat 29u IPv6 20980 TCP *:tproxy (LISTEN) tomcat@debian:/opt/tomcat$
And this is the end of this how-to. As usual suggestions are always welcome.