Host scores values in RHV Self Hosted-Engine setup

Solution Verified - Updated -

Environment

  • Red Hat Virtualization 4.x
  • Red Hat Enterprise Virtualization 3.x
  • ovirt-hosted-engine-setup

Issue

  • Hosts in RHV Self Hosted-Engine setup get different scores, what does that score mean?

Resolution

  • Score is a value between 0 to 3400. And it represents host' suitability for running engine VM.

    • 0 means unsuitable
    • 3400 means all is well
    • 2400 as well means a good status in older versions.

  • The score is calculated based on host status. Each monitor (ping, cpu load, gateway status, ...) has a weight and contributes to the score.

Score weights:

# NOTE: These values must be the same for all hosts in the HA cluster!
base-score=3400
network-score-penalty=1600
not-uptodate-config-penalty=1000
mgmt-bridge-score-penalty=600
free-memory-score-penalty=400
cpu-load-score-penalty=1000
engine-retry-score-penalty=50
cpu-load-penalty-min=0.4
cpu-load-penalty-max=0.9

Origin: ovirt.org

Old Score weights:

1000 - gateway address is pingable
800 - host's management network bridge is up
400 - host has 4GB of memory free to run the engine VM
100 - host's cpu load is less than 80% of capacity
100 - host's memory usage is less than 80% of capacity

Adjustments:

-50 - subtraction for each failed vm startup attempt
0 - score reset to 0 after 3 attempts, for 10 minutes

Diagnostic Steps

  • To get the score of the host, run:
# hosted-engine --vm-status
  • It will show status of each host and its score.
    For instance:
Status up-to-date                  : True
Hostname                           : 10.10.177.193
Host ID                            : 2
Engine status                      : {"health": "good", "vm": "up", "detail": "up"}
Score                              : 3400                 <<--------------------
Local maintenance                  : False
Host timestamp                     : 1408390728
Extra metadata (valid at timestamp):
    metadata_parse_version=1
    metadata_feature_version=1
    timestamp=1408390728 (Mon Aug 18 15:38:48 2014)
    host-id=2
    score=3400
    maintenance=False
    state=EngineUp

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