Use ES single redundancy by default

[pavolloffay]

Related to #501 (comment)

Signed-off-by: Pavol Loffay ploffay@redhat.com

[pavolloffay]

This string option is used to specify replica shards. Instead of exposing an integer ECL decided to expose a human readable string. The number of nodes is taken into the account when calculating the replica shards.

jaeger-operator/pkg/storage/elasticsearch.go

Lines 200 to 212 in 0d6bd5f

	func calculateReplicaShards(policyType esv1.RedundancyPolicyType, dataNodes int) int {
	switch policyType {
	case esv1.FullRedundancy:
	return dataNodes - 1
	case esv1.MultipleRedundancy:
	return (dataNodes - 1) / 2
	case esv1.SingleRedundancy:
	return 1
	case esv1.ZeroRedundancy:
	return 0
	default:
	return 1
	}

This should be defaulting to SingleRedundancy to keep backwards compatibility.

[pavolloffay]

Here we should be also checking the number of nodes. If it is a single node cluster the redundancy should be zero - https://angristan.xyz/elasticsearch-6-shard-replica-settings-for-single-node-cluster/ otherwise the health of the cluster will be yellow (not green :)).

I will create a separate issue for it.

[codecov]

Codecov Report

Merging #531 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #531   +/-   ##
=======================================
  Coverage   91.97%   91.97%           
=======================================
  Files          69       69           
  Lines        3501     3501           
=======================================
  Hits         3220     3220           
  Misses        196      196           
  Partials       85       85

Impacted Files	Coverage Δ
pkg/strategy/controller.go	97.54% <100%> (ø)	⬆️

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[objectiser]

LGTM
Although wouldn't it be easier just to add the node count check aswell and set to zero redundancy as part of this PR? Your call.

[pavolloffay]

I want to test it first.