I've been looking around from time to time for an app which would let me scan books from our collection at home and build a digital library - most useful for loaning books. I never found much on a PC, I did find
https://market.android.com/details?id=com.eleybourn.bookcatalogue&feature=also_installed#?t=W251bGwsMSwxLDEwNCwiY29tLmVsZXlib3Vybi5ib29rY2F0YWxvZ3VlIl0.
In short - yes, apps for desktop seem to be pretty much dead. I can't think of the last time I found a usable desktop application. At most, it's browser plugins like Nagios Checker. There are some "rich" applications or system management applications with rich clients, like InterMapper, but generally it's all web UI.
As Martha says, "It's a Good Thing".
Monday, 27 February 2012
Sunday, 29 January 2012
Charting Systems Using Cacti
There are a lot of great monitoring tools out there. I've posted many times before about Nagios and I could post still more on this great tool, but it's not the only tool I use. Another one is Cacti which is an excellent tool I've also mentioned before and it is mostly for graphing system resources.
Out of the box, Cacti will give you a lot of the basics especially when combined with SNMP. Disk usage, network interface usage, CPU, and memory. But what I really like about these great Open Source tools is that there are extensions readily available from the F/OSS community. With Cacti, you can extend by getting new host templates and data queries (and more). Here are some examples.
Disk IO - this is a new data query that tracks disk IO usage either in IOPS or MB/s. This is one of the simplest examples of how you can extend cacti. It comes as a xml file defining an SNMP query which you copy into your resrouces/snmp_query installation folder and as a data query template which you import through the Cacti UI. Once you've done this quick installation, you can add the disk io checks to any SNMP enabled host you are already tracking.
Dell PowerEdge Environment - this is another simple example which is the same as the Disk IO in that it is an SNMP query plus a data query template but there's 3 checks it adds. System ambient temperature, fan speeds, and system voltages. Its a great example of how Cacti as a generic tool can be tuned to target your specific operating environment whether you're a Dell shop, HP shop, or otherwise.
APC UPS Daemon - Another example of an application specific example. This one comes as a host template so its a collection of checks you can use to capture all the data queries on a host using APC UPS Daemon. A great example of where F/OSS tools *far* exceed the stock or closed-source tools provided by vendors. Rather than these cheesy brief inflexible views of how your system works as provided by APC that require overly large utilities to be installed, its quick, lightweight, and much more flexible to use the F/OSS tools.
Cacti is another of these great tools that works well in conjunction with other tools to give system administrators great insight into the operation of their network.
Out of the box, Cacti will give you a lot of the basics especially when combined with SNMP. Disk usage, network interface usage, CPU, and memory. But what I really like about these great Open Source tools is that there are extensions readily available from the F/OSS community. With Cacti, you can extend by getting new host templates and data queries (and more). Here are some examples.
Disk IO - this is a new data query that tracks disk IO usage either in IOPS or MB/s. This is one of the simplest examples of how you can extend cacti. It comes as a xml file defining an SNMP query which you copy into your resrouces/snmp_query installation folder and as a data query template which you import through the Cacti UI. Once you've done this quick installation, you can add the disk io checks to any SNMP enabled host you are already tracking.
Dell PowerEdge Environment - this is another simple example which is the same as the Disk IO in that it is an SNMP query plus a data query template but there's 3 checks it adds. System ambient temperature, fan speeds, and system voltages. Its a great example of how Cacti as a generic tool can be tuned to target your specific operating environment whether you're a Dell shop, HP shop, or otherwise.
APC UPS Daemon - Another example of an application specific example. This one comes as a host template so its a collection of checks you can use to capture all the data queries on a host using APC UPS Daemon. A great example of where F/OSS tools *far* exceed the stock or closed-source tools provided by vendors. Rather than these cheesy brief inflexible views of how your system works as provided by APC that require overly large utilities to be installed, its quick, lightweight, and much more flexible to use the F/OSS tools.
Cacti is another of these great tools that works well in conjunction with other tools to give system administrators great insight into the operation of their network.
Friday, 30 December 2011
Storing Passwords
The most effective way to manage your passwords for personal or professional use us to use a password manager. This allows you to manage unique logins for all the different resources you access (bank vs email vs general forums vs ...) and only have to maintain one master password. Pick a reputable password manager, like KeePass, and remember that backing up and restoring your password database is critical.
Keeping electronic copies is fine, but also consider keeping a hard-copy as well in a relatively secure location. One suggestion is that you print off your passwords every time you change your master password (annually is pretty minimal) but write that master password down on the print out so you can recover it if you forget it! Useful if you do cycle your master password frequently.
Keeping electronic copies is fine, but also consider keeping a hard-copy as well in a relatively secure location. One suggestion is that you print off your passwords every time you change your master password (annually is pretty minimal) but write that master password down on the print out so you can recover it if you forget it! Useful if you do cycle your master password frequently.
Friday, 16 December 2011
WiFi Routers and NAS
The last time I bought a new router was when the Linksys WRT54G was "the king" of home WiFi routers - and mostly because you can replace the useless stock firmware with DD-WRT. Otherwise, it was "a router". At the time, 4 years ago, which is like many generations in Internet time, you had to manually setup security on your WiFi AP still so you saw lots of open WiFi hot-spots like "Linksys" or "Dlink" around. Then the WiFi router manufactuers started providing security setup as part of their setup wizard so you see more SSID customization and security enabled. Now, apparently, everyone auto-configures security with a magic button called "WPS". Then you've got other features USB ports so you can run a file-server from a USB drive or print server and "guest networking" so you can isolate isolate your workstations from other users.
"WPS" - WiFi Protected Setup is definately a cool feature. It comes as a button on the router so when you press the button, its like the router goes into a sort of "security auto-config mode". WPS, if its supported on your client (I assume it's a software install), will then automatically configure your client and your router with strong security settings. It means no more default passwords and streamlining the security options for users who frankly don't need to have "WEP" as an option.
[Edit: WPS is broken and should be disabled on all routers that support it according to SANS.]
Guest networking is another cool feature on some routers. It is a separate SSID for, well, guests to use your WiFi from. It is isolated from your main network so that guests won't have access to, for example, your network attached printer or to your media collection you stream from your laptop to your television. This is just so cool for people who may be sharing their Internet connection with their neighbours or roommates but just don't want their surfing habbits to infect their own systems :)
And the USB ports. Many routers seem to have one or two USB ports on them which is interesting, but what's more interesting is what you can do with them. A lot of new routers have built-in file servers so as soon as you attach some storage, you can share files and folders from it to the PCs on your network. How convenient is that? Some routers have more sophisticated web interfaces than others and let you specify which folders are or aren't shared - but either way, if you're buying a new WiFi router anyhow and you get this feature, it means you get a functional NAS for the cost of a USB key or USB attached hard drive! *And* some routers are starting to come out with USB 3 - SuperSpeed USB which if you consider these routers have not only 802.11n speed on the WiFi but also Gigabit speed for the network ports, is an awesome feature.
And that's not the only thing you can do with the USB port - some routers will also act as a print server! So you attach your generic USB printer to the router, and it's now a network printer you can print to from any laptop or PC in the house. Talk about great value-added feature! I love it!
And did I mention that new routers are all now wireless N with Gigabit LAN interfaces? WiFi is still garbage and a ways away from being reliable outside very small deployments, but N is an improvement over previous specs. Interestingly, I found out the other day as well that if you run your router in "dual band" to support both N and G clients, your wireless speeds on both N and G suffer. So ironically if you have any wireless G clients, unless you really need your N devices to run at "slightly faster than G but nowhere near N speeds", you should still run G only.
Cool beans! I'm liking some of the features I'm seeing on the box these days from some of the WiFi routers. A nice change from the utter crap they used to shlep out where the only smart thing to do was check if you you run a custom firmware on the device and replace the junk software sold with it.
[Edit: WPS is broken and should be disabled on all routers that support it according to SANS.]
Guest networking is another cool feature on some routers. It is a separate SSID for, well, guests to use your WiFi from. It is isolated from your main network so that guests won't have access to, for example, your network attached printer or to your media collection you stream from your laptop to your television. This is just so cool for people who may be sharing their Internet connection with their neighbours or roommates but just don't want their surfing habbits to infect their own systems :)
And the USB ports. Many routers seem to have one or two USB ports on them which is interesting, but what's more interesting is what you can do with them. A lot of new routers have built-in file servers so as soon as you attach some storage, you can share files and folders from it to the PCs on your network. How convenient is that? Some routers have more sophisticated web interfaces than others and let you specify which folders are or aren't shared - but either way, if you're buying a new WiFi router anyhow and you get this feature, it means you get a functional NAS for the cost of a USB key or USB attached hard drive! *And* some routers are starting to come out with USB 3 - SuperSpeed USB which if you consider these routers have not only 802.11n speed on the WiFi but also Gigabit speed for the network ports, is an awesome feature.
And that's not the only thing you can do with the USB port - some routers will also act as a print server! So you attach your generic USB printer to the router, and it's now a network printer you can print to from any laptop or PC in the house. Talk about great value-added feature! I love it!
And did I mention that new routers are all now wireless N with Gigabit LAN interfaces? WiFi is still garbage and a ways away from being reliable outside very small deployments, but N is an improvement over previous specs. Interestingly, I found out the other day as well that if you run your router in "dual band" to support both N and G clients, your wireless speeds on both N and G suffer. So ironically if you have any wireless G clients, unless you really need your N devices to run at "slightly faster than G but nowhere near N speeds", you should still run G only.
Cool beans! I'm liking some of the features I'm seeing on the box these days from some of the WiFi routers. A nice change from the utter crap they used to shlep out where the only smart thing to do was check if you you run a custom firmware on the device and replace the junk software sold with it.
Wednesday, 19 October 2011
Source Control for Server Admin
So you manage a server, or a lot of servers alone or in a team, however you are doing this, you are going to be tweaking configuration files often and creating custom scripts for automation. There are two tools I use for revision control - RCS for configuration files (generally) and SVN for scripts (generally).
RCS. The classic. All the documentation you will ever need is in the man pages. Well that and some context for how to use it. RCS creates revision files in place. So if you change /etc/dhcpd.conf, it will create /etc/dhcpd.conf,v. This is a very useful setup when controlling local files in arbitrary locations - like most of /etc on most of your servers. There are a few caveats to keep in mind:
Now SVN is a proper centralized source control system. They have excellent documentation on setting up a repository. This is very useful for system admin scripts.
Although most system administration related scripts won't ever have "releases" or "branches", you probably still want to follow the SVN guide and create at least a trunk in case you ever do need to tag a specific version. There's no cost, so I use a trunk even though I've never used it because changing later is a problem.
With SVN you'll want to keep an updated local working copy ("tip") either on a shared NFS location or locally on each server. How you do it is up to you, just create a cronjob to run "svn update /path/to/tip" and then you can always run scripts from that path.
RapidSVN is a great tool, well maybe not great, but works very well for sys admin anyhow and its readily available. So check out your own working copy of the trunk with RapidSVN. I configured RapidSVN to use gedit as my standard editor and meld as my diff tool.
This gives you everything you need for day-to-day creating and maintain system configuration files and your toolbox of scripts for automated system maintenance.
RCS. The classic. All the documentation you will ever need is in the man pages. Well that and some context for how to use it. RCS creates revision files in place. So if you change /etc/dhcpd.conf, it will create /etc/dhcpd.conf,v. This is a very useful setup when controlling local files in arbitrary locations - like most of /etc on most of your servers. There are a few caveats to keep in mind:
- RCS will put revision files (the ,v files) in an RCS folder if present
- The default behaviour is to remove a file from its current path on check-in
- If there is no RCS folder (e.g. /etc/RCS), create it first
- mkdir -m 700 ./RCS
- Assuming your working folder is where the file in question is, this will create an RCS folder and protect it from other users (typically non-root)
- If a file doesn't exist in RCS, check it in first
- ci -u dhcpd.conf && co -l dhcpd.conf
- ci is short for "check-in", unlike SVN or CVS, "ci" is the command and not an argument to "rcs"
- The -u "unlocks" the file leaving it in place (so dhcpd can read it)
- co is "check-out" and -l "locks" the file for editing
- I always leave files checked out to capture changes by other users or by the system (like rpm)
- If the file does exist in RCS, check for any un-committed changes
- rcsdiff dhcpd.conf
- This does a diff against the last checked-in version by default but you can specify a version if you want to compare against earlier changes
- Check-in any un-committed changes or find the person who made the changes and make them do it
- The file should always be left checked-out (per above comment), otherwise check it out
- Make changes
- Check-in changes, and check-out the file for the next user
- ci -u dhcpd.conf && co -l dhcpd.conf
- Give a brief log message indicating what the changes were and again, leave the file checked-out to capture changes by the system or other users
Now SVN is a proper centralized source control system. They have excellent documentation on setting up a repository. This is very useful for system admin scripts.
Although most system administration related scripts won't ever have "releases" or "branches", you probably still want to follow the SVN guide and create at least a trunk in case you ever do need to tag a specific version. There's no cost, so I use a trunk even though I've never used it because changing later is a problem.
With SVN you'll want to keep an updated local working copy ("tip") either on a shared NFS location or locally on each server. How you do it is up to you, just create a cronjob to run "svn update /path/to/tip" and then you can always run scripts from that path.
RapidSVN is a great tool, well maybe not great, but works very well for sys admin anyhow and its readily available. So check out your own working copy of the trunk with RapidSVN. I configured RapidSVN to use gedit as my standard editor and meld as my diff tool.
This gives you everything you need for day-to-day creating and maintain system configuration files and your toolbox of scripts for automated system maintenance.
Saturday, 15 October 2011
Debugging Python Scripts
This is really just props for a site I found with a nice walk-through of using the Python Debugger - pdb.
http://pythonconquerstheuniverse.wordpress.com/2009/09/10/debugging-in-python/
pdb your built-in step-through debugger allowing you to inspect objects and all the usual things you need in developing a program.
http://pythonconquerstheuniverse.wordpress.com/2009/09/10/debugging-in-python/
pdb your built-in step-through debugger allowing you to inspect objects and all the usual things you need in developing a program.
Friday, 9 September 2011
Running the numbers
Two interesting tools popped up recently.
Good old Linux Counter has been passed down to a new maintainer. This is a classic project which attempts to get Linux usage data from user input. Its hard to tell if its particularly relevant, but it is interesting to see relative usage across platforms and by region. As for estimating global Linux use? Hard to be convinced this provides a good enough sampling to be very convincing. Nevertheless, I keep my machines at home registered there. Or at least some of them :P
Another one I really like is Debian Popcon which tracks popularity of Debian packages by installs and by "votes". Popcon is actually just a Debian package which phones home your installed package list and it is installed by default on some distros while not others. What I like about popcon is that when there are a wide variety of F/OSS tools available, you can check the list to see which tools are ranked highest so you can at least start by trying the most used tool rather than taking a total wild guess. For example, in looking for a SVN GUI tool, I did a "yum search svn" and there were a lot of hits. So I opened up popcon, search the list top to bottom for "svn" and took the highest hit which was a GUI tool which was RapidSVN. Well, then I checked with Dante which tool he used, but lo and behold, it was RapidSVN :)
Good old Linux Counter has been passed down to a new maintainer. This is a classic project which attempts to get Linux usage data from user input. Its hard to tell if its particularly relevant, but it is interesting to see relative usage across platforms and by region. As for estimating global Linux use? Hard to be convinced this provides a good enough sampling to be very convincing. Nevertheless, I keep my machines at home registered there. Or at least some of them :P
Another one I really like is Debian Popcon which tracks popularity of Debian packages by installs and by "votes". Popcon is actually just a Debian package which phones home your installed package list and it is installed by default on some distros while not others. What I like about popcon is that when there are a wide variety of F/OSS tools available, you can check the list to see which tools are ranked highest so you can at least start by trying the most used tool rather than taking a total wild guess. For example, in looking for a SVN GUI tool, I did a "yum search svn" and there were a lot of hits. So I opened up popcon, search the list top to bottom for "svn" and took the highest hit which was a GUI tool which was RapidSVN. Well, then I checked with Dante which tool he used, but lo and behold, it was RapidSVN :)
Subscribe to:
Posts (Atom)