Category: os

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Problem with mounting NFS on Mac OS X

Recently, I got a problem mounting my NFS shares. A shortcut to the /Volumes/Public placed on the desktop would mount the volume in read-only mode. A go to /Volumes and selecting the Public link would mount it in read-write.

Things I tried first:
-chgrp to guest, admin, 20 (group where my user is)
-chown to guest, myself, admin
-chmod to 777

Once a volume was mounted in read-only mode, it would only come back on read-write mode after a reboot of the NFS client and following the manual process. It must have been a while like this but it went unnoticed as when mounting from an application (not Finder), it would mount correctly.

I tried rebooting the QNAP (shame on me) but it would not change the mounts without rebooting the client.

So what did I learn so far. All NFS mounts are cached on the client. If you know how to clear the cache without rebooting, it would help me.

I also run nfsstat to find a lot of problems. Compared to some production systems, the number of nfs problems is abnormally high. (I will include some statistics to prove my point.)

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Groupware

People have heard about sharepoint, some people have heard about exchange…. Not difficult to miss if you consider the marketing engine that is behind it. Microsoft is desperately trying to change its business model now that Linux has become an low-cost alternative for people that are not wanting to pay for something that should be free.

The idea behind sharepoint is to tie people into an eco-system that will generate a future-proof eco-system. It took linux years to become ready for the mass market. Now that it is, Windows is only there for specific needs or for the ignorant. The only way windows will survive in the future, is to make it free for the masses.

Now this takes away a revenue stream for Microsoft. So they positioned a new one. Sharepoint is there to surplant Exchange, and to make people dependent.

Here are a few alternatives that already exist on the market (Article on groupwares).

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LDAP install guide CentOS

At first sight a good explanation on setting up an ldap on a CentOS machine.

First we start looking at a low profile CentOS machine to activate on my ESXi. Follow these steps:

1) Getting CentOS:
http://www.server-world.info/en/note?os=CentOS_5&p=make_media

2) Preparing the ESXi instance:
http://www.server-world.info/en/note?os=CentOS_5&p=vmware_esxi&f=3

3) Installing CentOS:
http://www.server-world.info/en/note?os=CentOS_5&p=install

4) Installing LDAP:
http://www.server-world.info/en/note?os=CentOS_5&p=ldap&f=1

5) Testing LDAP:
… to be done … I will update the article once finished.

e.g.: http://vuksan.com/linux/LDAP_authentication_under_Linux.html

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Single account management

My goal is to set-up a service that can replace my AD server or my Mac OS X server.

First requirement:

All user-account log-ins are stored on a central password server.
Users can log-in from Mac OS X machines using the password on the password server.
Users can log-in from Windows machines using the password on the password server.
Users can log-in on Apache configurations using the password on the password server.

Auxiliary requirements:

Home folders are configured on the password server.
Home folders are configured on the password server but residing on a third server.
Users can log-in from Unix machines using the password on the password server.

Final goal:

Allow unlimited window users on a domain without buying individual CALs.
or
Replace Mac OS X server to run on commodity hardware.

Comments and remarks are welcome.

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Multiple web-sites behind a single IP

In order to install multiple web-sites with the same IP, the web-sites have to be identified by DNS name. Secondly, one will want to have a different installation of apache for each of the individual web-sites.

I configured a set-up where I have a single forwarding proxy, and all different vm’s with individual web-services. With Apache 2.2, the config is as follows.

The firewall has a public ip, and is forwarding all requests on port 80 and port 443 to the private proxy. The proxy server has a private ip (e.g. 10.0.1.10) and is forwarding all requests to individual servers. I will present 2, but you can repeat as much as you want. The private servers are on 10.0.1.21 and up….

Activate your proxy includes by creating a symbolic link:
su root
cd /etc/apache2/mods-enabled
ln -s ../mods-available/proxy.load proxy.load
ln -s ../mods-available/proxy_http.load proxy_http.load

Edit /etc/apache2/httpd.conf and add following sections:
UseCanonicalName On
NameVirtualHost 10.0.1.10

<virtualhost 10.0.1.10>
ServerName webmail.mydomain.com
ServerAlias www.webmail.mydomain.com
ProxyPreserveHost On
ProxyPass / http://10.0.1.21/
ProxyPassReverse / http://10.0.1.21/
</virtualhost>

<virtualhost 10.0.1.10>
ServerName clientzone.mydomain.com
ServerAlias www.clientzone.mydomain.com
ProxyPreserveHost On
ProxyPass / http://10.0.1.22/
ProxyPassReverse / http://10.0.1.22/
</virtualhost>

… that is it… simple once you know but it took me a lot of time to find it out.