HOWTO

Technology

Renaming a Solaris zone

October 12, 2008 by 0 Comments

I needed to rename a zone on a Solaris 10 system earlier this week and here are some notes on how I did it.

The process of renaming a zone is essentially a task of renaming, editing and replacing strings in a series of (mostly XML) configuration files. All of the tasks below were carried out from the global zone on the system in question.

1. Shut down the zone to be renamed

# zoneadm -z <oldname> halt

2. Modify the configuration files that store the relevant zone configuration

# vi /etc/zones/index
Change all references of <oldname> to <newname> as appropriate
# cd /etc/zones
# mv <oldname>.xml <newname>.xml
# vi <newname>.xml
Change all references of <oldname> to <newname> as appropriate

3. Rename the main zone path for the zone

# cd /export/zones
# mv <oldname> <newname>

Your zone path may be different than the one shown above

4. Modify (network) configuration files of new zone

Depending on the applications installed in your zone, there may be several files you need to update. The essential networking files are:

# cd /export/zones/<newname>/root
# vi etc/hosts
# vi etc/nodename

But others containing your old host/zone name can also be found using this command:

# cd /export/zones/<newname>/root/etc
# find . -type f | xargs grep <oldname>

5. Boot the new zone again
# zoneadm -z <newname> boot

Technology

How to add a favicon to a WordPress Blog

March 18, 2008 by 0 Comments

I have a number of WordPress Blogs hosted from my domain and until recently hadn’t realised that I could have a different favicon for each one. In case you are unfamiliar with a favicon, it’s the little icon that appears beside the site name/address in your browser when you visit that site. For this site, that is a miniature picture of me!

Anyway, here is how to use a specific icon for any given blog (WordPress only):

  1. Place a copy of the icon file (favicon.ico) in the top level area where your WordPress blog has been installed.
  2. Edit the header.php file for the theme you are using. This is usually located in wp-content/themes/<themename> for WordPress blogs).
  3. Add the following line and save the file.

    4. <link rel="shortcut icon" href="favicon.ico" />

  4. Refresh the site from your browser and you’re all done!

Source: Amos Wong

Technology

Making scripts executable inside Subversion

February 1, 2008 by 1 Comment

The Problem

Every time you check out a script file from Subversion on a Unix system, the file is missing the execute permission and you have to manually perform a chmod +x every time. This usually happens if the file was either originally added without the permission set or if it was added to Subversion from a Windows system. But more to the point, it is extremely annoying.

The Solution

The solution to this involves adding an internal Subversion property called svn:executable to the script file(s) in question. The property can either be set using Tortoise SVN from a Windows system (as described by a posting on Late Night PC found by my colleague Máté Rácz) or can be done from the command-line as follows:

$ svn propset svn:executable true myscript.sh

Both methods work and required a SVN commit afterwards.

Technology

Syslog connections rejected using Syslog-NG on Solaris

January 25, 2008 by 2 Comments

The Problem

After an upgrade from Syslog-NG version 1.6.7 to version 2.0.5, our syslog server began reporting the following error each time an event was received from a remote host:

Syslog connection rejected by tcpd; from=’AF_INET(127.0.0.1:XXXXX)’

The syslog server was a Solaris x86 system which had a number of reverse SSH tunnels to several SPARC-based syslog clients. The version of syslog-ng was obtained from sunfreeware.com in binary form on both systems.

The Solution

It turns out that Syslog-NG 2.x introduced support for TCP Wrappers (which tcpd is part of) and thus, the settings in my /etc/hosts.allow and /etc/hosts.deny files were actually preventing syslog-ng from accessing port 514 on the local host. Adding the following entry to hosts.allow seems to have fixed the problem:

syslog-ng: localhost

Of course you will need to refresh/restart the inetd service after you do this (svcadm refresh/restart inetd).

Technology

Installing Nagios on Solaris

January 21, 2008 by 10 Comments

If you are not familiar with it, Nagios is an open source system and network monitoring application that keeps a watchful eye on hosts and services that you specify, alerting you when things go bad and when they get better. It was designed to run under Linux but, according to the creators, should also run on other Unix variants. With this in mind, I decided to try it out on Solaris.

Fortunately, they provide a very comprehensive User Guide and trust me, you’re going to need it. Suffice it to say, there is a section early in this document entitled Advice for Beginners which is pretty blunt about how tricky Nagios is to set up and, believe me, they are not wrong. Having said that, they do also say that once you get it running you will never want to be without it and I can definitely subscribe this this notion too.
Anyway, here are my notes from installing Nagios on Solaris:

My Setup

  • Solaris 10 (u3) for x86
  • Sun Studio 12
  • Nagios 2.10
  • Nagios Plugins 1.4.11

Building Nagios

I downloaded the Nagios source tar ball and unpacked it as a non-root user. Then, following the User Guide, I ran the configure script with no argument (implying I wanted all default settings) followed make all and this seemed to work fine.

Building Nagios Plugins

Nagios does most things by using other scripts/applications which it calls plugins. The Nagios website provides a collection of popular plugins for you to build. Once again, I did so using a configure command followed by a make all command. However, this did not go entirely smoothly:

  1. A number of the plugins failed to build citing an “undefined symbol: floor” error. This was resolved by adding -lm to the LIBS defined in line 328 of nagios-plugins-1.4.11/plugins/Makefile. This could probably also have been fixed by adding $(MATHLIBS) to the links statement of the affected plugins but that would have been more work.
  2. The check_dhcp module failed to compile citing several unknown data types (i.e. u_int8_t and u_int32_t). This was resolved by adding a -D__solaris__ to CPPFLAGS definitions at line 161 of nagios-plugins-1.4.11/plugins-root/Makefile
  3. The nagios-plugins-1.4.11/plugins-root/Makefile was also missing the same -lm link parameter as the plugins Makefile (line 221)

Once all of the above changes were make, all of the plugins seemed to build correctly.

Problems Found During Nagios Configuration

1. check_ping plugin did not work

No matter what way I configured the use of the check_ping plugin (in localhost.cfg, services section) it always reported:

CRITICAL – You need more args!!!
Could not open pipe:

A number of websites suggested that this was an IPv6 issue and that I should have used the --with-ipv6=no in my original call to the configure script when building the plugins. However, this was not the solution for me. It turns out that the definition of PING_COMMAND in nagios-plugins-1.4.11/config.h was empty and thus the check_ping plugin was actually making no attempt whatsoever to ping the requested host. I suspect that the reason for this is that I built the software as a non-root user which, on Solaris, does not have the ping command in it’s path (since ping is located in /usr/sbin on Solaris). Hence, the original configure script was unable to produce a valid definition for PING_COMMAND.

The solution to this was to edit nagios-plugins-1.4.11/config.h and add the following definition for PING_COMMAND (line 796)

#define PING_COMMAND “/usr/sbin/ping -s %s 64 %u”

The above command specific to Solaris and makes the Solaris version of ping behave like the Linux ping command. After this edit, I had to force a rebuild of the check_ping plugin (touch plugins/check_ping.c; make)

2. statusmap.cgi did not build

I only noticed this when I tried to view the Status Map section of Nagios. In short, the reason why this has not built is that I was missing a GD library on my Solaris system. The solution was to download and install a version of the GD library (and each of its dependent packages). I got mine from sunfreeware.com. The statusmap.cgi utility then built correctly and once I copied it to the libexec directory where Nagios was installed, it worked.

3. VRML Browser Plugin required

When I tried to view the 3-D Status Map options in Nagios, my brower kept launching a “Save As” dialog box. I turns out I needed to install a VRML plugin in my browser. I chose one called Cortona from Parallel Graphics. It seems to work fine in Firefox although, as yet, the 3-D Status Map view is more impressive than it is useful (for me anyway).

Conclusion

Nagios indeed took a long time to install, configure and set up. However, I can confirm that it was worth the effort and I am very pleased with it so far.

Technology

Running multiple instances of MySQL with Solaris Coolstack 1.2

January 21, 2008 by 0 Comments

We recently had a requirement to run two instances of MySQL on two separate Solaris systems (for the purposes of dual-master replication). The systems in question were both SunFire T2000s running Solaris 10 (U3) and Coolstack 1.2 and already had a previous/single instance of MySQL running (SMF service csk-mysql).

In the end, it was a relatively straightforward exercise in that all we really did was replicate the existing instance (control script, configuration file and manifest file) and change the necessary bits of the resultant files so that the new instance was sufficiently different to the old, in the end, producing two independent SMF services (csk-mysql1 and csk-mysql2). Specifically, the following files were created:

MySQL Control Scripts:
/opt/coolstack/lib/svc/method/svc-cskmysql1
/opt/coolstack/lib/svc/method/svc-cskmysql1

MySQL Configuration Files:
/etc/my1.cnf
/etc/my2.cnf

MySQL Manifest Files:
/var/svc/manifest/network/cskmysql1.xml
/var/svc/manifest/network/cskmysql2.xml

The manifest files were identical but for the name of the service and the control script they invoke. The control scripts were also identical but for the configuration file and DBDIR that they use and the difference(s) in the configuration files were mainly in terms of the port numbers and socket files used.

Beware

The only thing that caught us out was in modifying the control scripts (to tell them which configuration file they should use). This was done by adding a --defaults-file argument to the invocation of mysql_safe. However, you need to ensure that this argument is the first one you pass to mysql_safe. Otherwise, MySQL will launch will not load the correct configuration settings. This is not (well) documented so beware!

Also, when trying to access the new instances via the mysql client, you will need to add the -P and -S arguments.

Technology

Renaming a Solaris system

January 20, 2008 by 0 Comments

I’ve had to change the hostname of a number of Solaris systems over the past few weeks, some of which were (sparse) Solaris zones. Here are some notes for my/your future reference:

File Global Zones Non-Global Zones
/etc/nodename Yes Yes
/etc/hostname.ifname Yes No
/etc/hosts Yes Yes
/etc/inet/hosts Yes Yes
/etc/inet/ipnodes Yes Yes

Notes

  1. You will need to replace the ifname above with the name of the appropriate interface on your system.
  2. Depending on your system configuration, I may of course be missing some files. However, the above worked for me!
  3. None of the systems in question were running IPv6
Technology

Uninstalling Sun Studio

January 16, 2008 by 1 Comment

I recently had reason to upgrade to a newer version of Sun Studio on a Solaris 10 system. I had Studio 11 installed but needed to go to version 12 for better support of natively compiled Ruby Gem packages (e.g. mongrel). However, uninstalling Sun Studio is not the most readily documented thing in the world so, for my own future reference, here is the easiest way to do it:

# cd /var/sadm/prod/com.sun.studio_11
# ./batch_uninstall_all

After this, just follow the on-screen instructions …

Technology

Native Ruby Gems require Sun Studio 12 with CoolStack 1.2

December 6, 2007 by 0 Comments

A substantial number of Ruby Gem packages are written in Ruby itself and install quite neatly using a simple gem install command. However, a number of Gem packages are partly written in C and require some compilation during installation (e.g. hpricot, fastthread and mongrel). This requires you to have a C compiler on the system where you are installing the packages, which is a real pain, but that’s a gripe for another day.

We recently upgraded to CoolStack 1.2 but when we tried to install the Gem packages above, we ran into trouble when the installer attempted to compile the native code for the package. The compiler (Sun Studio 11) complained about the definition of the NORETURN macro in /opt/coolstack/lib/ruby/1.8/i386-solaris2.10/config.h as follows:

syntax error before or at: __attribute__
warning: old-style declaration or incorrect type for:
__attribute__
warning: syntax error: empty declaration
...
cc: acomp failed for hpricot_scan.c

It turns out that the new version of Ruby (1.8.6) that is included with CoolStack 1.2 contains some GCC-oriented macro definitions that Sun Studio 11 does not support. The solution was to upgrade to Studio 12.

Huge thanks go to Basantk for helping to resolve this.

Technology

Useful feature of Visual Studio XML editor

December 4, 2007 by 0 Comments

I had to do some Windows Mobile development recently (Visual Studio 2005, C# and .NET Compact Framework) and needed to create an XML file with text that contained some Scottish Gaelic characters in it. My understanding of XML files isn’t what it should be so I soon ran into a few funnies. Whenever i tried to load the document using the XmlDocument.load() method, the application threw an exception for which no explanation was given.

Since the amount of text was quite small, I simply pasted the the paragraphs I needed to display within my application (from Word) into a VI editor and saved the file with a .XML extension from there. I figured VI would do a decent job of removing all of the formatting from Word. However, doing this doesn’t really save the file as a proper XML file with the appropriate encoding.

Fortunately, Visual Studio provided a tidy solution. All I had to do is open my XML file from Visual Studio and then open the Properties of the document (View, Properties). Studio recognised that my file was an XML document (of sorts) and took a guess at the type of encoding it was using (Western European – Windows). I then changed the encoding to UTF-8 and re-saved the file with a different name (File, Save As), after which the XmlDocument.load() method worked just fine.

It looks like the re-saved file is now using 2 bytes for each of the special characters whereas before it only used one (I presume that the “U” in UTF-8 at work, as in, Unicode) and my Windows Mobile application worked a treat after that.