New Pipelines Runtime
Back in June we announced the release of our new CI/CD runtime for Bitbucket Pipelines, bringing with in new capabilities for customers and providing up to 8x faster CI/CD builds. The release of our new CI/CD runtime enabled customers to access the new 4/8x sizes for their builds, providing up to 16 CPU cores and 32 GB of memory to each build.
Additionally, the new runtime also enables us to offer a range of additional benefits to users – most importantly being the ability to provided dedicated CPU cores to each build, rather than access to shared CPU pools. One of the biggest benefits this will have for customers is related to a change being made in how we allocate CPU and memory to 1/2x builds (especially for 2x) once they are also moved to the new runtime.
As mentioned in June, the existing 1/2x step sizes would remain on the old runtime until September 17th, 2024, at which point they will be migrated over to the new runtime as well.
New CPU & memory allocation
Previously, builds in Pipelines shared CPU resources, leading to discrepancies between perceived and actual available compute power. Tools within builds would see 4 cores but only have access to about 1.8 cores of real compute.
The new Pipelines runtime addresses these inconsistencies by moving to a more dedicated CPU allocation model. The main change is that 1x builds will now show 2 cores instead of 4, while 2x builds remain at 4 cores.
Important: We want to emphasise that this is NOT a reduction in compute for 1x steps. In fact, 2x steps will see a significant INCREASE in compute allocation. The move to a dedicated CPU model means each visible CPU will provide more actual compute power.
As a result, 1x steps will maintain similar compute levels, while 2x steps will have approximately double the CPU allocation compared to before, aligning with their 2x memory allocation compared to 1x steps.
Bringing 1/2x steps to the new runtime
As mentioned back in June, the move to the new runtime also brought some changes, most importantly to IP addresses that Pipelines builds are served from that may impact customers that leverage IP Allow-listing.
On September 17th, 2024, we will be retiring the legacy Pipelines runtime for builds running on 1x and 2x sizes. Those step sizes will be automatically migrated to the new Pipelines runtime, as part of this process.
To be clear, 1x and 2x sizes are not being retired, they are simply being moved to the new Pipelines runtime.
As part of this deprecation:
- No changes are required in your Pipelines configuration.
- If you use IP allowlisting to control access to your internal networks from Pipelines, please update to the new IP address ranges for the new runtime as listed in the Pipelines documentation prior to September 17th.
For context, Atlassian has been running on this new runtime for it's internal CI/CD for an extensive period of time and has completed millions of builds with it, with no major incompatibility being experienced.
