I'm wondering if it is possible to use Nagios Core to restart, stop, or start services that are being monitored. I can't seem to find this answer anywhere using google or on any youtube videos. If you can restart, stop, or start a service, is there any sort of documentation that you know of?
Thank you.
You can use event handlers. Event handlers have many use cases. For example, you can:
Restarting a failed service
Entering a trouble ticket into a helpdesk system
Logging event information to a database
Cycling power on a host
etc..
Good and handy documentation you can find here: https://assets.nagios.com/downloads/nagioscore/docs/nagioscore/3/en/eventhandlers.html
Related
I need to check a group of servers (Unix, Linux) to know what kind of services, software (also version) are running there (check it once for a while and store it in database).
The idea is to have always fresh info about whole environment - its constantly changing. Perhaps you can suggest some solution that is already there?
Currently i am thinking about using Nagios or Cacti + plugins but I am not sure if this solution will be optimal.
Nagios is a very powerful monitoring solution (the best for me) : Open source, Compatible with both linux & windows, reporting & notifications via emails/SMS, Nice interface, Many many plugins...etc I've already worked with & I was very satisfied.
Check Nico Largo's Forum for Install. If you are not familiar to linux command search for FAN : Fully Automated Nagios which is a .iso where nagios is already in.
If you have any trouble during install or configuration post your questions there : https://serverfault.com/
Given that you want to poll for information on the system that can change dynamically, I would look at Check_MK.
It originally started as a plugin for Nagios that would poll a server for running services and generate the necessary configs for monitoring anything it discovered. Since then, it has evolved into a complete monitoring solution that provides its own complete ui (still based on nagios core), so you are safe in running this if you are familiar with nagios already.
See the website: http://mathias-kettner.com/checkmk_monitoring_system.html
You may need to select that you wish to view the "English" perspective of the site on first visit.
I'm using appengine-magic to set up a web application, more or less as described at http://www.digitalbricklayers.com/2012/03/geotasklist-in-jquery-mobile-and.html. The example works on my local machine, locations and tasks are added to a local datastore etc.
My question is if it is possible to interact with the datastore from within a REPL, e.g. call (ds/save! ...) etc. during interactive development? I ask because when I try I get:
NullPointerException No API environment is registered for this thread.
com.google.appengine.api.datastore.DatastoreApiHelper.getCurrentAppId
(DatastoreApiHelper.java:108)
I'm getting this error no matter if I use an eclipse+counterclockwise based setup or an emacs+slime based setup.
Thanks,
Joachim
There's a bunch of ways to do this.
The easiest way is to go to the admin console (http://localhost:/_ah/admin) and click on the "Interactive Console".
I use django-nonrel, which comes with a command to launch an interactive shell (manage.py shell). If you're not using django-nonrel though, getting it set up though, is somewhat involved. I suspect most of what's necessary is found in the setup_env() function in django-nonrel: https://github.com/django-nonrel/djangoappengine/blob/develop/djangoappengine/boot.py
Getting it all to work is a pain, good luck.
The solution I use 99% of the time is to use pdb and force the interpreter to break at a certain point in my app where I need to do some debugging. See this for instructions: http://eatdev.tumblr.com/post/12076034867/using-pdb-on-app-engine
appengine-magic lets you use App Engine services (like the datastore) as long as the application is running; see https://github.com/gcv/appengine-magic#app-engine-services — as long as you ae/start your application, it should work.
I've seen several posts that essentially state that UI components shouldn't run as a service. I understand the rational that no one can respond to UI events etc. But the fact remains that are are many automation tasks that are only possible with Windows forms.
Here is a couple of great examples:
I would like to build a url crawler
service that makes thumbnails of
webpages. Currently the only way I
see to achieve this is to try and
automate the .Net WebBroswer
component.
Automate the printing of MS-Word
docs.
Pre-Vista there was some tricks to get around this, but now there is none. My question is why is this the case, and what alternatives does one really have?
Lookup Shatter Attacks and Session 0 Isolation Feature.
Basically if two processes (of different users) share the same desktop, one process can potentially execute whatever code it wants in the other process by sending windows messages, and this was called a Shatter Attack.
There was a lot of discussion whether this was a design bug or not, and post Vista, Microsoft decided to remove any interactive desktop support for services as that was a potential security hole.
As an alternative, you can consider, running your image generation/printing code as a logged in user, who has access to an interactive desktop.
Like Moron said best thing to do is not run it as a service.
But perhaps you're stuck running it from a service anyway, because there is an existing framework of some sort that you're needing to run your code from.
So the workaround to that would be to write a server program that runs as a logged in user. You will hit that server program from your code the must be in a service. The server will do the work and return the results.
You can communicate between the 2 using WCF over named pipes as the transport, or whatever works. If that doesn't, you can use bare named pipes, or, tcp/ip on the localhost. Judging from your website in your userprofile, you should know all about localhost!
Technically, UI components requires started Windows Message Queue to work. You can run it from windows service (may be with allowed Interaction with Desktop, as far as I know this feature is disabled in Windows Vista and higher).
But things you are talking about is not UI components, it is COM components, and you can use it. At least MS Office, but it is not recommended by Microsoft, because memory leaks are possible. Latest MS Office has server edition, that can be used in application without user interface.
I am interesting in hearing if others have addressed release management for Silverlight applications.
I have a business application that is to be released shortly andam concerned about how to "release" updates to this application. Typically this application's users will leave the application open all day (and potentially all night) without reloading it.
What if there is is need to release an change that includes an web service interface change? How can this be deployed w/o causing errors on the client side?
We have grown so used to deploying ASP.Net apps by just dropping the latest code on the server. My only idea currently involves a client version number and a periodic timer on to check for updates.
I would love to know what others have done before implementing this.
Thanks,
Mike
I just answered a question on how to make sure that .xap files are not cached by the browser, which might be of some help:
Prevent Silverlight xap from being cached by proxy server
But that's no use if the users never reload your application. In my own application this is not a problem since users will be automatically thrown out whenever we deploy an update to the web service. But I like your idea with the timer, I would go with that.
Stating the obvious but don't do anything to annoy your users. E.g. could they spend twenty minutes entering data, nip off to the coffee machine and return to click Submit to find the timer has expired, noticed an update and their work is lost due to a forced restart?
If so, and I admit this hasn't had a lot of thought, if e.g. you have to make changes to the web service that break the current release, could you have the new web service version side-by-side such that users don't get thrown out until the timer has expired and the unit of work is complete? Or is this also stating the obvious?
For server code, i.e. endpoints just do as per normal. for the xap's I think you have a few options depending upon how you handle communications. You could have request contain a version number and if the server has been updated then force some code to reload the client, bit lame, messy but do-able. Perhaps a cleaner solution would be to control the clients session, which presumably is part and parcel with requests to the backedn. When you deploy a new version you could invalidate the client session, perhaps forcing a page refresh with custom logic. If your protocol is push base you could send a command to the client to do what ever you want, for many systems that are on all day its likely that this infrastructure would exist (if u've build it nicely :)). For instance our service layer is abstracted away from the repositories models and view models, in our case we'd could send a logout or perhaps a specific command to kick in some custom logic on the client informing the application is being updated and to refresh your browser when done. Our shell is light weight so our modules (basically other xap's) can be updated in time for the refresh.
I would recommend you to use a solution like mentioned in App Arch Guide:
The Guide Chapter I mean see Deployment considerations.
Divide the application into logical
modules that can be cached
separately, and that can be replaced
easily without requiring the user to
download the entire application
again.
Version your components.
Have you considered keeping a WCF polling duplex channel going that alerts the app when it needs to reload? In addition, you can have your WCF calls direct to a virtual directory that contains 'interfaced' calls. For example:
Silverlight app hosted at "x.x.x.x\Default.aspx"
Silverlight talks to WCF at "x.x.x.x\Version2\DataPortal.svc"
DataPortal.svc talks to a GAC (or otherwise base) assembly that can identify what version can handle what calls.
This way, if you upgrade to "x.x.x.x\Version3\DataPortal.svc", you can still make calls against Version2, assuming those calls have code to convert them to a Version3 concept.
This helps in cases where your line of business app has dynamic xap downloading ('main', 'customer', 'inventory', etc.) and you want to release them independently.
Background:
We run a content management platform that hosts 20+ separate websites - some intranets and some internet sites - so that have different end points routed for internal or external access.
We are currently upgrading our infrastructure - including software versions, hardware, changes of IP/VIP/DNS entries etc which affects all of the sites.
I want to be able to run a repeatable site test against all sites check everything is working fine and I'd like to do it from different end points (locally on each box in the cluster, from the cluster level, from the internet, from the intranet extra.
Anyone know of a simple tool that requires no sofware to install to run a repeatable regression test against a whole bunch of defined URL's?
I was thinking of a HTML page that I can run from different locations that is essentially a link checker.
Can anyone recommend a simple way to provide a level of automatic testing of our sites (in addition to our manual verification.
Thanks
Sounds like you're looking for Selenium: http://seleniumhq.org/
Edit
Wait, I think you mean 'Testing' them as in, check to see if they're online and reachable? Then I might just automate a series of ping or telnet commands, and check appropriate things. Would take a matter of minutes to write a little app in any language to do this.
There is all sorts of web site monitoring software available (check google, or ask for recos here). That's what you're looking for. There is a whole range from free to very expensive that monitor and stress your site from around the world.
Or you can write simple shell scripts that do what you want.
>> 'Testing' them as in, check to see if they're online and reachable?
Yes that's exactly it!! I was thinking the same - I could script something up but I thought I'd check first to see if someone has already done this - I guess not!
Thanks
Doesn't fit the "requires no sofware to install to run" part, and it's not necessarily super-cheap, but we've had great results with Radar Website Monitor for this kind of thing.