Woops! MySql didn't start when the server rebooted!

One of my customers had this problem today. I got a text message, "Lisha! Can you look at the server and tell me why mysql isn't working? I rebooted the server and now the website has an error. Something about Error #2002 and the mysql.socket."

It turned out that when they rebooted their LAMP server, the mysql demon didn't turn on with the rest of the services like the apache http demon. Luckily, this is easy to fix. I ssh'd to their server and got to work.

First, I checked to see if my hunch was right:
mysqladmin ping
mysqladmin: connect to server at 'localhost' failed
error: 'Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)'
Check that mysqld is running and that the socket: '/var/lib/mysql/mysql.sock' exists!

Yipes! Yup, you have no bananas (or mysql, as the case my be).

Next, I ran the mysql initialization script:
/etc/init.d/mysqld start
Starting MySQL: [ OK ]

Then check to see if it worked:
mysqladmin ping
mysqld is alive

Ah, yes. All better!


Next time, we can make mysql demon startup at boot time. On a Red Hat type system you can run the following code as root (or via sudo) to run the initialization script automatically at boot:
ln -s /etc/rc.d/init.d/mysqld /etc/rc.d/rc3.d/S98mysql

Collecting mail from external servers on Zimbra

Do you have Zimbra users who want to pull mail into their Zimbra accounts without having to press "Get Mail" or "Get External Mail" every time? It's easy.

In the Zimbra server's command line, running as user zimbra, try:
zmprov gc default | grep zimbraDataSourcePollingInterval
If you get a response, the number it gives you is the number of seconds between checks of the external mail boxes. If you don't get any response, that means that the zibraDataSourcePollingInterval isn't set yet. Set it like this:
zmprov mc default zimbraDataSourcePollingInterval 180
Now the external mail accounts will be checked every 3 minutes.

But wait!! There's a problem. If your users created secondary accounts before you did this, their mail might not get picked up on schedule. (This is certainly the case as of 5.0.0_GA_1869.) So, you need to set the polling interval for each of your users' data sources manually -- or with a script that you write yourself.

For each user, check what datasources they have now:
zmprov gds myuser |grep DataSourceName
where myuser is the name of the user, of course. Then, for each user modify the data source with the command:
zmprov mds [username] [dataSourceName] zimbraDataSourcePollingInterval [seconds]

For example:
zmprov mds myuser Migration\ Account zimbraDataSourcePollingInterval 180
Notice the \ and space in "Migration\ Account" in my example. The name of this data source is "Migration Account". If you have spaces in your data source name like I do here, then you need to use the backslash (\) to escape the space. Otherwise, the system thinks that the next word is part of the next option or command in the line. (This is pretty standard *Nix-ish behavior, but if you're a newbie it can throw you off.)


(The info for this post was found at http://www.zimbra.com/forums/installation/11487-solved-receiving-mail-multipop3-server.html and through personal experience with this problem last week...)

Locking Down Root

Having an active root user is generally not a good thing. If the machine is used by lots of people and several individuals do superuser tasks under the root user, you have no way to track who did what in the event that someone decides to get evil. And of course, hackers like to get root access, because it lets the do anything that they want. You don't want that, so let's lock root up.

First, make sure that you have super user abilities when root is locked. If you don't already have sudo access, use root now to add yourself into the /etc/sudoers file. (I'll write an article about that soon. In the meantime, use man sudo to learn more.)

Now, lock root. Get out of root, if you are in it already, and as a user with sudoers privileges type
sudo passwd -l root
Check your work with
sudo passwd -S root
You should see something like
$ root L 09/11/2007 0 99999 7 -1

The option -S gives you the status of a user. It gives you the user name, then the status (L = locked, NP = no password, P = password), the date of the last change, and then the minimum age, maximum age, warning period and inactivity period for the password.*


Root is now locked. You can't log into root directly any more, and will have to run superuser tasks through sudo. There is still a cheater way around it, though. You can
sudo su
and then you will be root again. (I'll explain how to fix that in the sudo article.)



* Minimum age for a password says that you can only change the password ever so many days. Maximum age says that you have to change your password every so many days. Warning period is how long before maximum age is reached that the system should start warning you that you have to change your password. Inactivity period is how long after a password is expired that the login should be completely locked out. If you don't change your password before maximum age is reached, then the system will generally let you log in and immediately change your password before moving on. Once you've hit the days in inactivity period, though, you don't get a chance. It just won't let you in at all at that point. All of these ages are expressed as a number of days.

Creating A New *Nix User

The easiest way to create a new user on the command line is:
sudo useradd george
sudo passwd george

But that's not always enough. Let's say, for instance that you want people to change their password the first time that they log in and then again every three weeks. Let's set georgette up like that:
sudo useradd georgette -c "Georgette Userina"
sudo passwd georgette
(give her a throw-away password)
sudo passwd -e -x 21 georgette


Here's what we just did:
sudo = "superuser do" (do this as if you are root)
add user georgette with the comment (-c) "Georgette Userina" (-c is usually used for the user's full name)
give georgette a password she can use the first time she logs in
expire georgette's password immediately (so she has to change it when she next logs in) and then expire (-x) her password every 21 days.

Need a short term user? Maybe you have a contractor working with your company for a short time or a friend that's hanging out at your house for the next two weeks and needs access to your Ubuntu desktop while he's there. Here's how to do it:
sudo useradd sammi -c "Sammi Shortimer" -e 2008-03-10


Here we use the -e option with useradd to expire the account after March 10, 2008.

If you do most of your new user adds with the same special options, you can set those things as default in the file /etc/login.defs

MacBook Air

Oh, me wants one. Me wants one bad.



Yeah, yeah, it's not Linux or OpenBSD. But it is *Nix-ish, and it's so purty. And I need a new computer, I really, really do.

In real life, though, I don't have that kind of cash to throw down right now. It looks like I might be borrowing an old Mac laptop from Lior Kesos of Linnovate shortly, so that will take care of my laptop needs. For the house I'll purchase a PC and put Linux on it (as usual). My little guy and I can make a homeschooling project out of setting up a Webcam + software to create a multi-touch, gesturable interface. I'll let you know how it goes here when we do it.

Wish list for my new computer:
1. bluetooth (to hook up with our cell phones)
2. webcam for video chat with far off friends and relations
3. multi-touch, gesturable track-pad like input
4. everything I already have on my current laptop
(you know, like 802.11g/n, region-free dvd movie viewing, KDE desktop, some fun games, etc...)

Mail, Calendar and Collaboration

We just set up Zimbra at work, and I'm really pleased with it. But I'm a little wary of the fact that Yahoo! just bought Zimbra. What will happen to this platform next? Nothing bad, I hope...

Here's why I like Zimbra, as opposed to the other open source groupware server packages out there. (Where to start?)

1) Zimbra is made up of familiar pieces. It uses the Unix philosophy, which is to write relatively small applications and then glue them together to do big jobs. In that vein, Zimbra uses Postfix, Apache, and other tried and true tools at its base.

2) Zimbra can be used with all your usual clients. It works with IMAP or POP3, and even has an available (non-open) Exchange-like piece that you can use for your (shudder) Outlook users. It also has nice, standards based things like an ical version of your calendar, which you can use to connect up with standards-friendly calendar clients.

3) Zimbra has a fantastic Web-based client. It's all AJAXy and buzzword compliant, but that's not what's great about it. My favorite part about it is actually reason #4...

4) Zimlets. Zimlets let you create all sorts of extensions that will work in Zimbra. Here at this company we're in the process of planning the next generation of their whole in-house software system, and I'm putting Zimlets at the core of several pieces of that software architecture. Customer service, billing, accounts payable, marketing, and supply-chain will all have direct access between their respective job-function-related applications and Zimbra, both ways. For instance, a CS rep will be able to read an email sent to service@..., mouseover the customer name to see that customer's key info or mouseover the order number and get info about that particular order. Click on either one and the cs rep will go straight to the full editable customer or order page. All this, of course, will be based on Zimbra group permissions which will be sync'd up with the user/group permissions on the Web interface for our customer service tools.


As you can see, I'm very excited about the possibilities. This is why I keep working in this industry. Fun stuff. :)

Improving Web Research

This isn't my usual level of geeky tips, but something that comes up a lot for anyone who has to learn on the Web all the time. "Back in the day" when I was in college, I read books and highlighted them as I went, or else I'd take copious notes on 3x5 cards. Then, when it was time to review or to gather the information to put into a report, I'd have easy access to everything. On the Web it's a bit different. I can read stuff, but until now, it's been a bit more difficult to gather the details I need from a specific page along with notes and references I would have written in margins or on cards. Bookmarks alone just don't cut it.

There are a few tools out there now that are aiming to fix this problem, though. I use Google Notebook right now as my main computer-based note taking tool, but I'm looking around to see if there is anything better.

Google's Notebook tool is actually rather nice. It works with a browser plug-in that sits in the right-hand corner of my browser status bar. I can click it, and the notebook opens up. I can have several "notebooks" that each hold different sorts of information. I can type notes myself, or I can highlight something in my browser and then drag it to an open notebook, or press "clip" in the notebook plug-in, and I get a little note with the text or images I've highlighted plus a link back to that page. In the Web page for the notebook (though not in the little plug-in version) I can see the date that the note was taken, which is important for citations and the like. I like it, I'm just wondering what else is out there before I get so much data into this notebook system that migration would simply be a major pain.

There is a tool called i-lighter that looks very interesting. It allows you to use your mouse like a highlighter on the screen, and then it saves your highlighted text, along with any other notes that you want to write. Problem? It's a Windows application. Sure, I could use it with Wine, but unless it completely rocks the universe, I don't see a reason to do that.

I have heard about other pieces of software in this category that are under development, but I have yet to experiment with any of them. If you have any recommendations, I'd love to hear about them!