Zalenium 1 Requests Waiting For A Slot To Be Free

Over the years Selenium users have used Selenium Gridextensively to reduce the execution time, to perform cross browser testing, toperform multiple OS testing. Although grid provides us all these benefits, theycome with their own cost. If you look at the issues that we are facing now withgrid are:

Sets the period of time over which requests are tracked for a given source IP address. Rate-limit-requests Sets the maximum number of requests that will be accepted from a source IP address during the rate-limit-period. To track the http requests rate, a stick-table named “Ratelimit-' will be created. Example, If the rate-limit-period is set. Please consider following 2 requests: 1. In the free course for every section there seems to be a Skill Test Section which says 'Score 80% or higher to pass'. This section is unavailable as part of the free course. It says 'Authorization Required, You must be a subscriber to access this content.' Due to which course completion remains approx 75%.




  • Have astable grid to run UI tests with Selenium
  • Maintain itover time (keep up with new browser, Selenium and drivers versions)
  • For longerexecutions Java process will run out of memory.
  • Restarting the nodes in case of issues
  • Scaling upfor more tests is tedious.

Zaleniumprovides the solution for above problems. It is a docker-selenium based solution which can start a Selenium Grid in seconds, a grid that scalesup and down dynamically to run your tests in Firefox and Chrome. It works outof the box in docker and Kubernetes. Zalenium also provides the video recordings of your tests and live preview of your test execution.

Zalenium Setup:

1. Make surethat the latest Docker is up and running. (check here for instructions to install and run)

2. Open commandprompt/ terminal and run the below commands to pull the Docker images fromDocker hub.
  • docker pullelgalu/selenium
  • docker pulldosel/zalenium

Selenium 1 Requests Waiting For A Slot To Be Freely


3. startthe Zalenium-selenium-grid by executing the below command
  • Windows:

4. Zaleniumgrid is ready now for the execution. Initially zalenium creates one chrome andone firefox container. If you need more containers, we have to specify them asparameters like below while launching our grid.

5. Now write aselenium test using remote webdriver. Look at the below script for reference.


In above script, we need to specify the IP and port address of the machine where Zalenium is running as URL.

6. If you runthe test now, it will execute in zalenium-grid.

LivePreview:

As discussedabove, Zalenium provides live preview of your execution. You can watch your test execution live onceyour tests are triggered. You can access the live preview from the below link:

http://localhost:4444/grid/admin/live#
To Auto-refresh,add ?refresh=numberOfSeconds to refresh the view automatically.
E.g.http://localhost:4444/grid/admin/live?refresh=20 will refresh the page every 20seconds.

DashBoard:

  • Zaleniumalso provides very useful dashboard for monitoring the test results. From thisdashboard you can replay those recorded videos. Below is the link for thedashboard.

http://localhost:4444/dashboard/#

  • You can replace localhost for the IP/machine name where Zalenium is running
  • Click onCleanup to remove all videos and logs from the local drive and the dashboard.Also resetthe dashboard via http://localhost:4444/dashboard/cleanup?action=doReset orcleanup via http://localhost:4444/dashboard/cleanup?action=doCleanup

To stop thedocker containers spun through Zalenium, simply exit Zalenium grid using thebelow command

Integrating with Cloud Solutions:

Zaleniumusually creates containers only with Chrome and firefox. If you want to executeyour tests in any other browser or any other platform, you can still use othercloud based platforms such as Saucelabs, Browser stack. Zalenium enables you tointegrate these platforms with the existing zalenium-grid.
Belowcommand helps to integrate with Saucelabs:
You can visit Zalenium Site for more details.

1.

More

  • Chris Dag's post entitled Resource reservation prevents parallel job starvation

2.

The Problem

  • A large parallel job may sit in a queue for a long time, indeed may never be scheduled, even though its priority is high (and growing) because lower priority smaller jobs will barge past the large job as sufficient slots become available to run the latter.
  • Nothing in fairshare, urgency, etc comes to the aid of the large job.
  • What is needed: block the lower priority jobs completely until enough space becomes available to run the larger job.
  • You can use resource reservation to guarantee that resources are dedicated to jobs in job-priority order.

3.

A Solution: Resource Reservation

Free

4.

Back Fill

Selenium 1 Requests Waiting For A Slot To Be Free Download

Backfilling enables a lower-priority job to use resources that are blocked due to a resource reservation — but only if there is a runnable job whose prospective run time is small enough to allow the blocked resource to be used without interfering with the reservation.

5.

Detecting/Monitoring/Spotting R-R Jobs which are in the Queue, Waiting

Selenium 1 Requests Waiting For A Slot To Be Free Play

  • Why isn't my job running? There are empty nodes!
The Problem
If a larger job has a r-r it will block a smaller job from jumping past itin the queue and grabbing compute nodes as they become free. For example,two compute nodes may be free on which a waiting 24-slot job could run, butit will be blocked by an 48-slot r-r job. How is the owner of the 24-slotjob to know?
Use qstat -j <job-num>
For example,N.B. If the job has no r-r, then the output is NOT reserve: n; thereis no reserve line in the output at all.
qstat -g c?
No! Shows only advance reservations, not resource reservations.