SSH Check with Content String Matching

NodePing is happy to announce the new SSH check. In its simplest use, the new SSH monitoring provides a real SSH connection for monitoring those critical SSH services, but our check can do much more than that.

Not only can we monitor the availability of your SSH services on any port, but we can also optionally have the check log in and verify the presence, or absence, of a particular string in the login response. Pairing the SSH check with a login script makes it much more powerful and flexible. With it, you can monitor much more than SSH.

In the example below, we’re going to set a login script that checks server load, available memory, and disk usage. We’ll use its simple ‘PASS‘ or ‘FAIL‘ output to trigger email and SMS alerts from NodePing when the 1 minute load average goes over 4.0, when available memory drops below 50MB, or when the disk becomes more than 90% full.

The script is a simple BASH script that relies on commonly installed programs like ‘top’, ‘free’, and ‘df’ to determine the ‘PASS’/’FAIL’ status for each of the things we’re monitoring. It’s not the prettiest thing, but it seems to work well on an Ubuntu server.

#!/bin/bash
# Load average limit
# A quad-core server may be maxing out CPUs at 4.0
LOADLIMIT=4;
# Free memory floor in MB.
FREEMEMLIMIT=50;
# Disk usage in percentage, but without the percent sign. 
DISKUTILIZATION=90;
# Path to the disk partition you want to monitor.
DISKPATH='/dev/sda7';

LOAD=`top -n1 | grep 'load average' | awk -F" " '{print $12}'`;
LOAD=${LOAD:0:4}
LOAD=`echo "$LOAD > $LOADLIMIT" | bc`
if [ $LOAD -eq 1 ]; then
echo "LOAD:FAIL";
else
echo "LOAD:PASS";
fi

MEMUSAGE=`free -m | grep '^Mem' | awk -F" " '{print $4}'`;
MEMUSAGE=`echo "$MEMUSAGE < $FREEMEMLIMIT" | bc`;
if [ $MEMUSAGE -eq 1 ]; then
echo "MEM:FAIL";
else
echo "MEM:PASS";
fi
DISKSPACE=`df | grep "$DISKPATH" | awk -F" " '{print $5}'`;
LEN=`expr "$DISKSPACE" : '.*'`;
LEN=`echo "$LEN-1" | bc`;
DISKSPACE=${DISKSPACE:0:$LEN}
DISKSPACE=`echo "$DISKSPACE > $DISKUTILIZATION " | bc`;
if [ $DISKSPACE -eq 1 ]; then
echo "DISK:FAIL";
else
echo "DISK:PASS";
fi
# logout right away
# This SSH user is restricted for security purposes
exit;

We saved this script as ‘mylogin.bash‘ in our user’s home folder and then edited the /etc/passwd file, replacing the shell ‘/bin/bash‘ with ‘/home/testuser/mylogin.bash‘.  Don’t forget to make the script file executable with something like

chmod 0755 /home/testuser/mylogin.bash 

Now when our test user logs in, we see something like:

Last login: Thu Apr 12 22:41:33 2012 from 127.0.0.1
LOAD:PASS
MEM:PASS
DISK:PASS
Connection to 127.0.0.1 closed.

It’s the response text above that will be checked against our user defined content string. In our SSH check configuration, we’ll set the ‘Content string‘ dropdown to ‘Does not contain‘ and type ‘FAIL‘ in the text field.  Now when NodePing’s probe servers login via SSH and find the word ‘FAIL‘ in the response, I’ll get a notification!

But the notification just says that the SSH check failed. We won’t know what failed.  It could be the load, memory, or disk.  Instead of logging in to see, I’ll be lazy and create three separate SSH checks, all with the same host and login information, but have one check for the string ‘LOAD:FAIL‘, another check for ‘MEM:FAIL‘, and the other ‘DISK:FAIL‘.  I’ll label the one that checks the load average a nice informative name like “Load Average on test server” and the other checks something similar. Now my SMS notification say something like “SSH Check failed for: Load Average on test server“, letting me know exactly what’s failing.

NodePing provides 1000 checks run at up to 1 minute intervals for only $10/month so you’re running out of reasons not to monitor everything. If you don’t have a NodePing account yet, sign up for our free 15-day trial and kick the tires.  We think you’ll like it.

The above example is fairly simple.  You can write your own login scripts in Node.js, Python, etc to check statuses for databases, VPN connections, virus definition updates,… dang near anything!  You can find information on how to configure your SSH checks in our documentation.

How will you use the new SSH check with content string matching?  Let us know in the comments below.

FTP Check Now Looks for Files Too!

Until today, the NodePing FTP check was fairly basic but we’ve rolled up our sleeves to add the awesome sauce and are proud to announce our new and improved FTP monitoring check.

Features:

  • Monitor FTP on any port, not just 21
  • Supports anonymous logins
  • Verify FTP user logins (optional)
  • Verify the existence, or non-existence of a file on your FTP server (optional)

Detailed information about how to configure your FTP checks can be found in our documentation.

The “file exists” feature in particular can be a huge help for those who wish to do more than just check to see if their FTP service is currently running. We’ll send you a notification if that important file goes missing from your FTP service – or if a particular file suddenly appears! This can be used to receive an alert when an application error log file gets created.  Or you could write your own scripts for internal processes that trigger NodePing SMS alerts by touching files on your FTP server.

The new enhancements are available on your account now at NodePing.  If you don’t have a NodePing account, you can sign up today for a free 15-day trial and for $10 a month you can monitor 1000 servers and get unlimited email and international SMS alerts.

SSL Certificate Check

An SSL certificate is an important part of serving up secure websites. It puts the ‘S’ in HTTPS and gives your visitors that warm fuzzy feeling when they see that padlock in their browsers. But those SSL certificates don’t last forever. Most have to be renewed every 1-3 years and should you forget and let that certificate expire, your visitors will be met with an ugly “This Site is Untrusted‘ message instead of your great content. Let NodePing keep an eye on your SSL certificates with our new SSL check available today.

Monitoring your SSL certificate with NodePing will allow you to receive notifications if the certificates is nearing its expiration, is replaced with an invalid certificate, or if your webserver is incorrectly serving it. You can also configure how many days in advance of expiration you’d like to receive the notification, giving you time to renew and install a new certificate without interruption.

The new SSL check is just one more link in your comprehensive server monitoring chain. NodePing is happy to keep an eye on your SSL certificates. If you don’t have an account yet, sign up for a free 15 day trial at http://nodeping.com.

Let us know what you think of the new SSL check in the comments below.

Monitoring results now available in JSON and CSV formats

Many of our customers monitor their own customers’ websites, or they monitor services about which they have to periodically report availability and incident statistics. Many of them would like to include status information in their own dash boards or integrate results with other data in reports. All of that calls for the data to be available in formats that can be easily used by scripts, or easily imported into spreadsheets.

NodePing has now added the ability to retrieve monitoring results in JSON and CSV format. JSON is ideal for scripting situations, such as creating your own dashboards or views of the data. CSV is great for loading the results data into your spreadsheets for analysis or creating reports for customers or management.

Both of these formats are available as extensions to our public reporting feature, which we added a while back. When you turn on public reporting, you are given a UUID that identifies that check. The same UUID can be used to access the data as a public report (you need to know the UUID, which gives you some control over who sees it, but does not require a login), as JSON output, or as a CSV download.

You can read more about these features and see some sample URLs on our Reporting page in the NodePing Documentation.

Monitoring password protected websites

Some of our customers have asked us to add basic authentication to our HTTP checks. They want to be able to check the availability of web pages that are protected from public access by a login. So, we have enhanced our HTTP and HTTP Content checks to support basic authentication.

This means that when you set up HTTP or HTTP Content checks in NodePing’s website monitoring service, you can now include a username and password in the URL. The format is username:password@host. We already supported both http and https requests and arbitrary ports in the URL. The following URL examples are all in a valid format for NodePing HTTP and HTTP Content checks (although these are fictitious, don’t actually use these URL’s in your checks), with this enhancement rounding out the list:

People who use this feature should be aware that HTTP basic authentication is not secure, which is one of the reasons we had not included it until now. This has required a small change to our Terms of Service to point out that we aren’t responsible for confidential information that is included in checks such as this. If you choose to include a username and password in your checks, you should take normal precautions to protect your data, including making sure that the login used for the checks is limited to no more access than is needed for the check, and avoid reusing passwords.

If you have any questions about basic authentication in HTTP or HTTP content checks, or about any aspect of our website monitoring, please don’t hesitate to ask us by emailing info@nodeping.com.

Server Monitoring from Europe

NodePing is happy to announce we’ve added a new region to our check locations. You can now choose to run your checks from our North American or new European regions… or both!

Website Monitoring

We’ve heard from many of our customers with a presence in Europe that a check location on that side of the pond would be a huge benefit. Thanks to our great providers, IntroVPS and RobHost, we added 4 new probe servers in the following locations:

  • London, England
  • Amsterdam, Netherlands
  • Falkenstein, Germany
  • Bucharest, Romania
Check out our FAQ for ip addresses and more information on our check locations.

We’ve also introduced the idea of a ‘default region‘ for your NodePing account. For new customers, you’ll set your default region when you sign up. Current customers have their default region set to ‘North America’. The default region can be changed in the ‘Scheduling‘ tab. When you create checks, they will be automatically run from your default region. You may, of course, decide to run any check from any region (including multiple regions and ‘worldwide’) by simply choosing the desired region from the check configuration when you create it. You can also change an existing check by selecting a different region in the check configuration at any time.

When you assign your checks to a region, they will be run from a random server in that region. If an ‘up/down’ event is detected, NodePing will immediately and automatically recheck from other servers in that same region. The number of rechecks is based on your configuration of the check – the default is 2 rechecks. After verifying the ‘up/down’ status on other servers in the same region, we’ll send out your configured email and SMS notifications.

Everything is included with NodePing so the new European region checking is already part of your flat-rate $10 a month subscription which includes your 1000 site/server checks, unlimited logins, contacts, contact groups, emails and international SMS. If you’re not already a customer, sign up for your free 15-day trial.

We’re already planning to add even more check regions to NodePing – Oceania maybe? South America? East Asia? Let us know in the comments what new region you’d like to see added next.

Contact Groups added to NodePing

We have been getting a lot of great feedback and suggestions from our users over the months since we launched the NodePing monitoring service. One feature that many people have asked for is the ability to group contacts and assign notifications to groups of contacts rather than just to individuals. Today we’re excited to announce that we’ve added Contact Groups to the service.

You can now create a Group, assign individual addresses or phone numbers to each contact group, and then set the Group to receive notifications for individual checks. So, for example, you could create a Developers group and a Systems group and have each assigned to different sites or servers you are monitoring. Then if the makeup of that part of your team changes you can change who belongs to the group without having to change each of the notifications.

One way we use this feature in the NodePing team is to assign SMS numbers to a group called SMS. Then we can easily set notifications to all of our phones together. For us, SMS notifications generally mean “Do something about this now!” and it makes it easy to assign key services to this notifications contact group. You could also use it to group all of a person’s contact methods easily for notifications that should get to them wherever they are. So for example you could create a “Shawn” group and include all of Shawn’s email addresses and phone numbers in that group. Then notifications will automatically be sent to all of his addresses.

As with contacts, there is no limit on the number of contact groups you can use in NodePing. You can mix and match contact methods in all kinds of ways, to suit your particular needs. We’re happy to now get to use this feature ourselves, and we hope it will further enhance the usefulness of our service to you as well.

There are a few smaller enhancements and adjustments in the release today as well, and we have more coming. Thank you to everybody who has chosen NodePing for their server and website monitoring. Thank you also to everybody who has given us feedback and suggestions. Please keep them coming!