Bug 1770920

Summary:	[doc] Allow entry for RHV manager in flat DNS '/etc/hosts'
Product:	[Red Hat Storage] Red Hat Gluster Storage	Reporter:	Shivraj <shipatil>
Component:	doc-Deploying_RHHI	Assignee:	Laura Bailey <lbailey>
Status:	CLOSED CURRENTRELEASE	QA Contact:	SATHEESARAN <sasundar>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	rhhiv-1.6	CC:	asriram, fiezzi, godas, mkalinin, myllynen, rhs-bugs, sasundar, stirabos, storage-doc
Target Milestone:	---
Target Release:	RHHI-V 1.7.z Async Update
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:
Clones:	1779525 (view as bug list)		Environment:
Last Closed:	2020-02-26 08:06:00 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1779525
Bug Blocks:	1804071

Description Shivraj 2019-11-11 13:48:03 UTC

Document URL: 
https://access.redhat.com/documentation/en-us/red_hat_hyperconverged_infrastructure_for_virtualization/1.6/html/deploying_red_hat_hyperconverged_infrastructure_for_virtualization/rhhi-requirements#rhhi-req-network

Section Number and Name: 

3.5. Networking


Describe the issue: 

Above section ask to setup the DNS and resolve Fully-qualified domain names that are forward and reverse resolvable by DNS  which  are required for all hyper-converged hosts and for the Hosted Engine virtual machine that provides Red Hat Virtualization Manager. 

Suggestions for improvement: 

Add information to use flat DNS entry instead of DNS server when customer doing single host isolated installation

Additional information: 

Customer is doing deploying RHHI-V to possibly hundreds of isolated edge clusters (locations) where there is no data center infra and services like external DNS available. In fact, often the RHHI-V nodes are the very first nodes that are being setup in these environments so deployments must be fully self-supporting meaning that customer cannot expect an external DNS being available.

Due to this customer is adding all the RHV Hosts and RHV-M systems to '/etc/hosts' on each and every system in the cluster. With RHHI-V 1.5 this worked just fine, both installation and operation. However, due to installer changes in RHHI-V 1.6 we need to remove RHV-M from /etc/hosts prior RHV-M deployment.

While the above is technically doable for customer, it would seem to indicate that there has not been much testing for RHHI-V deployments without an external DNS service.

Thus customer would like to have isolated edge RHHI-V installations without external DNS to be documented to make sure the product has the needed flexibility for these use cases and to make sure customer is using the most suitable process for deployments here.

Comment 2 SATHEESARAN 2019-11-11 14:07:23 UTC

For now moving this bug to RHHI component of RHGS, but actually this ask doesn't have anything to do with RHGS.
When RHV could support such requirement, then RHHI-V could also do.

I think as of now RHV has this requirement of 'forward and reverse DNS resolution' requirement.

@Simone, Do you know ?

Comment 4 Sahina Bose 2019-11-21 07:02:58 UTC

" Due to this customer is adding all the RHV Hosts and RHV-M systems to '/etc/hosts' on each and every system in the cluster. With RHHI-V 1.5 this worked just fine, both installation and operation. However, due to installer changes in RHHI-V 1.6 we need to remove RHV-M from /etc/hosts prior RHV-M deployment."

Doesn't the option Edit hosts entry - do this automatically? Why is there a need to remove RHV-M from /etc/hosts, is this due to the local VM entries that are created?

Comment 6 Marina Kalinin 2019-11-27 04:45:20 UTC

Hi Simone,

Can you please review this request and provide feedback. 
While I completely understand why RHV requires full DNS, in case of RHHI-V, no DNS deployment is necessary by design and we need to consider a solution for such deployments.

Thank you,
Marina.

Comment 8 Marko Myllynen 2019-11-27 11:31:00 UTC

(In reply to Marina Kalinin from comment #6)
> 
> Can you please review this request and provide feedback. 
> While I completely understand why RHV requires full DNS, in case of RHHI-V,
> no DNS deployment is necessary by design and we need to consider a solution
> for such deployments.

If using network_test=ping and listing all Hosts / RHV-M consistently in /etc/hosts of RHV node (Hosts+RHV-M) then does RHV still require "full DNS"? How are isolated/edge RHV installations supposed to work?

Thanks.

Comment 9 Simone Tiraboschi 2019-12-02 09:29:50 UTC

In the initial implementation ovirt-ha-agent was periodically checking network status on the host sending a ping to the default gateway.
After customer requests we introduced alternative ways to check the network status including a DNS query which is now the default.
If a DNS server is not available the ping method is still there and fully supported so yes, in that case the user has just to set 'he_network_test: ping' to complete the picture.

Comment 10 Sahina Bose 2019-12-03 05:14:37 UTC

Moving to doc team to add the edge installation scenario (without DNS server) in the docs.

Comment 11 SATHEESARAN 2019-12-04 06:54:06 UTC

Qualification of this type of deployment without DNS server is required, before documenting the procedure.
I will raise the test-only bug for verification of the same.

If everything works good, the same could be documented

Comment 12 SATHEESARAN 2020-02-01 05:55:34 UTC

(In reply to SATHEESARAN from comment #11)
> Qualification of this type of deployment without DNS server is required,
> before documenting the procedure.
> I will raise the test-only bug for verification of the same.
> 
> If everything works good, the same could be documented

This effort is now Qualified with RHV 4.3.8 and RHGS 3.5.1
In this case, IP addresses are used instead of FQDNs and RHHI-V deployment