This machine runs a lot of services and I don't use all of them. After breaking several of them and not noticing (again), I decided to finally set up service monitoring. After some research, Monit was relatively easy to set up and seems to meet my needs. I figured other people might want some examples of how to use it, so this post describes how to set it up and you can see my config file at the end.
Why Monit
The link you posted is to the API documentation of M/Monit, the commercial SaaS that makes use of Monit, the open source watchdog software. (I agree that the naming is confusing). The OP wanted an API to interact with Monit, specifically to build an alternative to M/Monit. – Kenny Rasschaert Jul 28 '17 at 13:54. Monit can monitor several kinds of resources: the running system itself, individual processes (such as network services), filesystems, or particular files and directories. If none of these are appropriate, you can configure it to run custom scripts to test the conditions that you are interested in. ## Monit has an embedded web server which can be used to view status of ## services monitored, the current configuration, actual services parameters ## and manage services from a web interface. Sudo monit status The Monit daemon 5.6 uptime: 0m System 'example.com' status Running monitoring status Monitored load average 0.00 0.01 0.05 cpu 0.5%us 0.4%sy 0.0%wa memory usage 115132 kB 22.9% swap usage 0 kB 0.0% data collected Mon, 22 Dec 2014 16:50:42 Filesystem 'rootfs' status Accessible monitoring status Monitored permission.
My use-case is one server monitoring itself. The obvious question is 'who monitors the monitor?', but my main concern is not noticing services I don't use. If the entire server is down I'll probably notice eventually. A bigger problem is that I'm not testing the firewall rules and routing. A separate server really would be ideal, but since I can't run it from home (ISP port filtering blocks SMTP), I'd have to pay for another VPS, and it doesn't seem worth it right now.
Monit Examples Ubuntu
I've worked with sysadmins in the past who liked Nagios, so that was my first choice for this, but it's complicated to set up and extreme overkill for monitoring one server. I looked at Sensu too, and it seems nicer but still overkill. I chose Monit because it's easy to setup (see next) and the barebones UI doesn't matter to me (I just want a basic up/down status and emails).
Setup
Write 2 6. To install Monit on Fedora, you run:
Configuration
The edit config files step is by-far the longest. First you'll want to edit /etc/monitrc and set your mail server and who to sent alerts to. For me this was just:
If you're using a remote mail server, you probably need to configure a user name and password. I also uncommented the eventqueue lines so alerts won't be lost if the mail server goes down.
The only other thing I changed in this file is the set httpd port .. section, where I changed the admin password and removed the localhost restriction (so I can access it remotely at http://status.brendanlong.com).
I put the rest of my configuration in individual files in /etc/monit.d. For example, monitoring of things accessed at 'brendanlong.com' is in a file named /etc/monit.d/brendanlong.com and http://etherealspring.com/ is in /etc/monit.d/etherealspring.com. This is just personal preference, but it will be easier to handle package updates this way, and I should be able to find things faster.
To write these config files, refer to the Monit documentation. Monit can check a lot of things like processes and system health, but I'm a believer in checking the thing you actually care about. I don't care what processes are running or what files exist, I just want to sure that you can get the correct pages from each HTTP server and the other servers are responding in reasonable ways. To do that, I used check host rules exclusively.
Host rules take the form:
The unique name part is annoying, since Monit creates a rule for your server automatically, and you can't add to it (as far as I can tell — email me if this isn't true). I got around this by naming it 'localhost' instead of 'brendanlong.com'.
Graphicconverter 10 1 0 – graphics editor with powerful features. The part I had the most trouble with was figuring out the rules. Here's what I found:
Monit Examples
- You'll always want a
port = [num]rule. This works how you'd expect. - If you're testing one of the supported protocols, add a
protocolsection. It supports all of the major protocols like HTTP(S), SMTP(S), IMAP(S), etc. If you tell it the protocol, it will ensure that the endpoint not only connects, but gives a reasonable response. - For protocols that have logins, you can give a
usernameandpasswordand it will test if the login succeeds. - For HTTP, you can give the expected
statusand text that should be in the response withcontent. - Order matters. For example,
protocol http status 200 content = 'Brendan Long'is valid, butprotocol http content = 'Brendan Long' status 200is not. See the syntax in the documentation for the correct order. - If you don't set
protocol, it will just test if a TCP connection succeeds. You can do more complicated checks withsendandexpect(send a text or binary message and check the response). - You probably want to setfault tolerance for some rules. In my case, the connection to my SMTP server would randomly fail, but it doesn't really matter as long as a retry works. I made it quieter by adding
for 3 cyclesto that rule.
The link you posted is to the API documentation of M/Monit, the commercial SaaS that makes use of Monit, the open source watchdog software. (I agree that the naming is confusing). The OP wanted an API to interact with Monit, specifically to build an alternative to M/Monit. – Kenny Rasschaert Jul 28 '17 at 13:54. Monit can monitor several kinds of resources: the running system itself, individual processes (such as network services), filesystems, or particular files and directories. If none of these are appropriate, you can configure it to run custom scripts to test the conditions that you are interested in. ## Monit has an embedded web server which can be used to view status of ## services monitored, the current configuration, actual services parameters ## and manage services from a web interface. Sudo monit status The Monit daemon 5.6 uptime: 0m System 'example.com' status Running monitoring status Monitored load average 0.00 0.01 0.05 cpu 0.5%us 0.4%sy 0.0%wa memory usage 115132 kB 22.9% swap usage 0 kB 0.0% data collected Mon, 22 Dec 2014 16:50:42 Filesystem 'rootfs' status Accessible monitoring status Monitored permission.
My use-case is one server monitoring itself. The obvious question is 'who monitors the monitor?', but my main concern is not noticing services I don't use. If the entire server is down I'll probably notice eventually. A bigger problem is that I'm not testing the firewall rules and routing. A separate server really would be ideal, but since I can't run it from home (ISP port filtering blocks SMTP), I'd have to pay for another VPS, and it doesn't seem worth it right now.
Monit Examples Ubuntu
I've worked with sysadmins in the past who liked Nagios, so that was my first choice for this, but it's complicated to set up and extreme overkill for monitoring one server. I looked at Sensu too, and it seems nicer but still overkill. I chose Monit because it's easy to setup (see next) and the barebones UI doesn't matter to me (I just want a basic up/down status and emails).
Setup
Write 2 6. To install Monit on Fedora, you run:
Configuration
The edit config files step is by-far the longest. First you'll want to edit /etc/monitrc and set your mail server and who to sent alerts to. For me this was just:
If you're using a remote mail server, you probably need to configure a user name and password. I also uncommented the eventqueue lines so alerts won't be lost if the mail server goes down.
The only other thing I changed in this file is the set httpd port .. section, where I changed the admin password and removed the localhost restriction (so I can access it remotely at http://status.brendanlong.com).
I put the rest of my configuration in individual files in /etc/monit.d. For example, monitoring of things accessed at 'brendanlong.com' is in a file named /etc/monit.d/brendanlong.com and http://etherealspring.com/ is in /etc/monit.d/etherealspring.com. This is just personal preference, but it will be easier to handle package updates this way, and I should be able to find things faster.
To write these config files, refer to the Monit documentation. Monit can check a lot of things like processes and system health, but I'm a believer in checking the thing you actually care about. I don't care what processes are running or what files exist, I just want to sure that you can get the correct pages from each HTTP server and the other servers are responding in reasonable ways. To do that, I used check host rules exclusively.
Host rules take the form:
The unique name part is annoying, since Monit creates a rule for your server automatically, and you can't add to it (as far as I can tell — email me if this isn't true). I got around this by naming it 'localhost' instead of 'brendanlong.com'.
Graphicconverter 10 1 0 – graphics editor with powerful features. The part I had the most trouble with was figuring out the rules. Here's what I found:
Monit Examples
- You'll always want a
port = [num]rule. This works how you'd expect. - If you're testing one of the supported protocols, add a
protocolsection. It supports all of the major protocols like HTTP(S), SMTP(S), IMAP(S), etc. If you tell it the protocol, it will ensure that the endpoint not only connects, but gives a reasonable response. - For protocols that have logins, you can give a
usernameandpasswordand it will test if the login succeeds. - For HTTP, you can give the expected
statusand text that should be in the response withcontent. - Order matters. For example,
protocol http status 200 content = 'Brendan Long'is valid, butprotocol http content = 'Brendan Long' status 200is not. See the syntax in the documentation for the correct order. - If you don't set
protocol, it will just test if a TCP connection succeeds. You can do more complicated checks withsendandexpect(send a text or binary message and check the response). - You probably want to setfault tolerance for some rules. In my case, the connection to my SMTP server would randomly fail, but it doesn't really matter as long as a retry works. I made it quieter by adding
for 3 cyclesto that rule.
Monit Examples Medical
Examples
Here's the config file for brendanlong.com. At some point I'll make it do more extensive testing for Minecraft and SyncThing, but this gets me 90% of what I wanted:
