nova schedule: change concurrent builds over group of servers

asked 2019-01-16 06:04:05 -0500

ansh gravatar image

Hello everyone.

I have tested multiple instance creation in my environment and faced up with need to hold on instance creation task until previous instance will be created. My shared storage is slow and when multiple VPSes are trying to spawn at the same time some of them will fail due to timeouts.

I did next:

  • Increased the block device mapping timeout. Options block_device_allocate_retries, block_device_allocate_retries_interval in nova

  • Configured the Image-Volume cache to prepare volumes in advance.

But it gave me possibily to create about 10 instance in row without fail. I have thinked about how to schedule instance creation and force nova create VPS one by one. I have looked on max_concurrent_builds, max_io_ops_per_host nova options but they work only on for single compute host.

Is there a way to set nova-scheduler concurrent instance builds over group of servers?

My enviroment is OpenStack 17.1.3, Shared Storage - Ceph. Thanky for paying attention.

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