I'm trying to use an EC2 instance to run several Selenium chromedrivers in parallel. When I run just one, it works fine. But as soon as I start a second Selenium process, both processes fail (as in, page loads hit max timeouts after a couple minutes).
I'm using a t3.large instance, which has 8gb RAM and 5Gbps of network bandwidth. It's not a cheap instance and costs $2 per day. I'm surprised that with these specs, it can't handle two concurrent Selenium processes because my personal laptop has no problem handling 4+ Selenium processes.
Additional info: I'm using pyvirtualdisplay on the EC2 box.
Wondering if I'm missing something here that is causing the poor performance.
I've been running a standalone chrome selenium server in AWS for a while, and am used to seeing the active browser sessions listed in the web console (located at <selenium_host>:4444/wd/hub/static/resource/hub.html) where I can see screenshots, kill sessions and more.
I recently migrated over to running the standalone selenium server inside a docker container and noticed that the web console is still visible but all the buttons are disabled and no sessions appear even when active browser sessions are running.
There are no issues with the selenium functionality itself, I just would like to be able to view the active sessions and cannot figure out how to fix this.
I'm setting up a test infrastructure using Azure & Docker - Selenium HUB and Chrome Images
Running the latest version of Ubuntu on AZURE
System Configuration
Ubuntu:16*
Docker: Latest Version
RAM: 6GB
SSD: 120GB
Able to run automation script in the Chrome containers without any issue, if the number of containers is <=10.
When I scale up the numbers, entire system freezes and not responding and the tests are not running.
PS: I'm also mounting /dev/shm:/dev/shm when creating the containers.
What should be the optimal system configuration to run a minimum of 75 containers?
6GB RAM for 75 containers means ~ 80 MB/container. That too you want to run a firefox/chrome inside? Which may be running headless/without display but that doesn't mean they are not memory hungry.
You would need to park 500MB memory/container for such nodes. You can set a memory limit but as soon as your container goes above it, poof!!!. The container is dead and so is your browser and your test. Best is to either use Docker Swarm to deploy a self healing Selenium Grid
Or you can use https://github.com/zalando/zalenium as mentioned by #Leo Galluci.
PS: I wrote an article on how to setup Grid on swarm http://tarunlalwani.com/post/deploy-selenium-grid-using-docker-swarm-aws/. You can have a look at the same to get an idea at the horizontal scaling your grid
I am looking for ways to set up like a central 'hub' for Selenium in my work, allowing anyone to access in within the company. For example, Tester A writes test scripts, the Person B can run without having to manually copy over the test scripts to their local workstation)
So far, I've only thought of installing Selenium in a VM which will then execute as per normal. But if I run Selenium Grid, it will run VMs within VM (?). My only concern with VMs is that it'd run slowly.
If anyone can think of a better solution or recommendation please do give me some advice. Thank you in advance.
One idea. You can create an infrastructure combining Jenkins/Selenium/Amazon.
The following is my solution from another post.
You can do it with a grid.
First of all you need to create a Selenium hub with an EC2 ubuntu 14.04 AMI without UI and link it as a jenkins slave to your Jenkins master. Or as directly a master. What you want. Only command line. Download Selenium Server standalone. (be careful on downloading the version. If you Download the Selenium3Beta, things could change). Here you can configure the HUB. You can also add the Selenium Hub as a service and configure to run automatically at server start. its important that you open the Selenium default port (or the one that you configured) so the nodes can connect to it. You can do that on the Amazon EC2 console when you have created your instance. You just need to add a security group with an inbound rule for TCP in the port you want for the IPs you want.
Then, you can create a Windows server 2012 instance server (for example, that's what I did), and do the same process. Download the same version for Selenium and the chromedriver (there is no need to download any firefoxdriver for Selenium versions before Selenium3). Generate a txt file and prepare the Selenium command to link to the HUB as a NODE. And convert it to *.bat in order to execute it. If you want to run the bat at start you can create a service with the task scheduler or use NSSM (https://nssm.cc/). Don't forget to add the rules to the security groups for this machine too!
Next, create the Jenkins server. You can use the Selenium Hub as the Jenkins master or as a slave.
Last step is configuring a job to be run in the Jenkins-Selenium machine. This job needs to be linked to your code repository (git, mercurial...) Using the parametrized build plugion for jenkins you can tell that job to pull the revision you want (where every developer can pull the revision with the new changes and new tests) and run the Selenium tests in that build with the current breanch/revision and against one unique selenium. You can use ANT or Maven to run the Selenium tests in Jenkins.
May be it's complicated to understand because there are so many concepts here but it's robust and it works fine!
If you have doubts, tell me!
If Internet Explorer is not one of the browsers on which you must run your automation tests, I would recommend that you consider docker selenium.
Selenium is providing pre-configured docker images for both Selenium Hub and Node ( refer here for more information ). For making use of docker selenium all you need to do is find a machine (preferably unix machine), install docker on it by following instructions detailed here and then start the hub and node by starting off those containers. In the case of docker you can literally transform a VM (or) a physical machine into a VM farm and yet not have to worry about slowness etc., because I believe docker is optimised for these and it runs your VM as a process.
Resorting to using Amazon cloud for running your selenium nodes is all fine, but if you have corporate policies that prevent in-coming traffic from the internet into your intranet region, then I am not sure how far Amazon cloud would be useful.
Also remember that Jenkins is not something that is absolutely required but is more of a good to have part in the setup because it would let anyone run their tests from a web UI. This will however require that all your tests are checked-in and made available in a central version control system in your organization.
PS : The reason why called out Internet Explorer as an exception is because IE runs only on windows and there are no docker images (yet) for windows. All the docker images are UNIX based images.
So that we may perform front-to-back web UI testing, we are using Selenium and ChromeDriver to automate page loads/interaction as part of our testing pack.
This is behaving as expected during developer testing (on a developer's local machine), but we are struggling to perform these checks as part of our continuous integration build.
Our server plant is *NIX based, and all of our CI infrastructure runs on these machines. So that we may test Chrome under Windows (our delivery mechanism), we have configured a Selenium Grid. When the CI tests run, they access the grid, in order to locate a Windows node to run the tests on.
We have had a Windows desktop provisioned solely for the purpose of running these tests. This contains our standard enterprise build of Windows 7. This machine will be periodically rebooted in-line with the IT department's update policy.
In an effort to ensure the Selenium server is always running, we have added the Selenium Server (running in "node" mode) as a Windows service. The selenium Server is configured to start-up ChromeDriver to invoke the simulated user-interaction.
However, when running the tests from CI they fail due to timeout. Our working theory is, the system user that is running the service cannot create interactive windows. A web search has raised reference to the "Session 0" problem, but with little to no constructive advice on how to move forward.
Starting the Selenium Server process manually from an interactive session is not a viable solution, as this is leading to brittle tests - which are failing due to an infrastructure problem, rather than a genuine test regression.
How can we have an instance of Selenium Server started via a Windows Service whenever the system reboots, that is capable of launching Chrome instances?
It could be easily done with NSSM.
Installation of services looks like these:
nssm install seleniumhub java -jar C:\selenium\selenium-server-standalone-2.45.0.jar -role hub -hubConfig C:\selenium\hub.json
nssm install seleniumnode java -jar C:\selenium\selenium-server-standalone-2.45.0.jar -role node -nodeConfig C:\selenium\node.json
It provides easily way to remove service if needed:
nssm remove seleniumnode confirm
Add destination to nssm to your PATH variable and run from console as admin
UPDATE April 2021
NSSM is not supported for more than 3 years. So please consider other options like winsw or any other. WinSW does the same job as NSSM and allows to keep run configuration in xml.
You cannot run Selenium Grid as a windows service ever since Windows Vista. Microsoft calls it "Session 0 Isolation". You could do it in Windows 2000 or XP but since the time that Vista came out, Microsoft no longer will let Grid interact with the desktop (or any other UI programs for that matter). Regardless of the fact that you still see that "interact with desktop" checkbox, it is a red herring. So, you MUST run Selenium Grid in the foreground on that server in order for it to get access to the session. If it is running Windows Server, you could in theory have multiple sessions and leave Grid running in the foreground on one of the non-zero user sessions.
Right now you can't help it - it used to work fine in session 0 but for the past few days after chrome update only works for interactive sessions.
Related bugs:
https://code.google.com/p/selenium/issues/detail?id=8029
https://code.google.com/p/chromium/issues/detail?id=422218
My preferred solution to this problem (and my default choice for running Selenium Grid as a service) is to use a simple tool called AlwaysUp. It has a free 30 day trial to try it out.
What to do:
Download AlwaysUp
Configure AlwaysUp to start the Selenium Grid node on startup
Configure AlwaysUp to run the Selenium node as a specific user (not the default System user)
This way the the node will run as a service, survive machine restarts and work with the latest version Chrome.
If the user account you use to login to the machine is different from the user account you specify to run the node as a service then you will not see the browsers pop up on the desktop as they are running in a different user session. The end result is that it is almost identical to running as a normal service but gets round the Session 0 issue.
Yeah, you should use NSSM. Important is, that you add your windows account in the "Log on" tab, or any other valid account. If you run your node with the "Local System account" option, you will get the session 0 problem. With a normal user session, the nodes run smoothly invisible in the background :)
we don't use selenium GRID, we were disappointed with its stability. We use a "Jenkins Grid", that is jenkins slaves nodes on various servers.
The slaves are services with the interact with desktop flag. They run as services with NSSM, and the SERVICE_INTERACTIVE_PROCESS flag. Making sure that NoInteractiveProcess is set to 1 (cf https://learn.microsoft.com/en-us/windows/desktop/services/interactive-services).
We don't have the fancy features of the grid (that is balancing according the browser types slots). Instead, we have Jenkins balancing the test jobs using a slave node or another.
Initially we did not use the interact with desktop flag, having browsers to run without "real" display, but the behavior was not very stable (especially with resize commands).
Hope this helps.
As I explained on this thread, I found that using a small paid tool FireDaemon Pro saved me a lot of time from trying to configure NSSM and other free tools.
It works well in the background, and restarts Selenium along with the server, which was my main requirement for running Selenium Standalone Server as a Windows Service.
This free tool would probably do it:
http://yajsw.sourceforge.net/
For that to work, you need a wrapper.conf file and a script to run the YAJSW wrapper. I takes time to read the documentation, but it is a free solution.
I wrote an example shared here, that installs JBoss7 as a Windows service.
Of course, you can simplify my example by a lot.