Tag Archives: high availability

VMware Host Isolation Response in a Nutanix Environment #NoSAN

Posted on by
4

I was recently discussing the Nutanix solution with a friend of mine and fellow VCDX, Michael Webster (@vcdxnz001) and he asked what the recommended Host Isolation Response is for Nutanix.

At this stage I must advise there is no formal recommendation, but an Official vSphere on Nutanix Best Practice guide is in the works and will be released asap.

Back to my conversation with Michael, Being that Nutanix is an IP Storage solution, my initial feeling is that Host isolation Response should be set to “Shutdown”, but I didn’t go into any more detail with Michael, so I thought it best to post a quick explanation.

This post also assumes basic knowledge of vSphere as well as the Nutanix platform, for those of you who are not familiar with Nutanix please review the following links prior to reading the remainder of this post.

About Nutanix | How Nutanix Works | 8 Strategies for a Modern Datacenter

So back on topic, in other posts I have written for IP Storage, such as (Example Architectural Decision – Host Isolation Response for IP Storage) I have concluded that “Shutdown” was the most suitable setting and recommended specifying isolation addresses of the NAS controllers.

But as Nutanix changes the game and has one virtual storage controller per ESXi host, so does this change the recommendation?

In short, No, but for those who are interested, here is why.

If we leave the default isolation address, (being the default gateway for ESXi Management), in the event the gateway is down, it will trigger an isolation response even if the rest of the network is operating fine, thus an unnecessary outage would occur.

If we configure das.isolationaddress1 & 2 with the Management IP address of any two Nutanix Controller VMs (192.168.1.x , 192.168.1.y in my below diagram) then an isolation response will only be triggered if both Nutanix Controller VMs (CVMs) are not responding, in which case, the VMs should be Shutdown as the Nutanix cluster may not be function properly with two Controllers offline concurrently as its configured by default for N+1 (or replication factor of “2” in Nutanix speak).

The below is a high level example of the above configuration.

NutanixHostIsolation

Related Articles

1. Example Architectural Decision – Host Isolation Response for a Nutanix Environment

2. Storage DRS and Nutanix – To use, or not to use, that is the question?

3. VMware HA and IP Storage

vSphere 5.1 Single Sign On (SSO) Configuration – Architectural Decision flowchart

Posted on by
3

The below is the second architectural decision flowchart in my new series and covers a new feature in vSphere 5.1, Single Sign On.

There has been a lot of discussion around “Best Practices” for SSO, I have taken the approach of creating this flowchart with as many scenarios as possible.

I would recommend that you validate any configuration the flowchart results in is suitable for your environment prior to implementing into production.

The flowchart is designed to be used as a guide only, not a definitive decision making resource.

This also compliments some of my previous example architectural decisions which are shown in the related topics section below.

A special thanks to Michael Webster (VCDX#66) @vcdxnz001 & James Wirth (VCDX#83)@JimmyWally81 for their review and contributions to this flowchart.

SSO flowchart V1.0

Related Articles

1. Example Architectural Decision – SSO deployment mode over Active/Active Datacenters

2. vCenter Single Sign-On – Part 1: What is vCenter Single Sign-On?  – By Justin King @vCenterguy

3. vCenter Single Sign-on Part 2 – Deployment options – By Justin King @vCenterguy

4. vCenter Single Sign-on Part 3 – Availability  – By Justin King @vCenterguy

5. vCenter Single SIgn-On – Part 4: Pre Install Requirements – By Justin King @vCenterguy

6. Disabling vSphere 5.1 Single Sign-on – Long White Virtual Clouds – By Michael Webster @vcdxnz001

7. VMware KB: Multisite Single Sign-On deployment best practices

8. Where is the Best Practice Guide for SSO? | VMware Support Insider By 

Example Architectural Decision – vSphere 5.1 Single Sign On (SSO) deployment mode across Active/Active Datacenters

Posted on by
Reply

Problem Statement

What is the most suitable deployment mode for vCenter Single-Sign On (SSO) in an environment where there are two (2) physical datacenters running in an Active/Active configuration?

Requirements

1. The solution must be a fully supported configuration
2. Meet/Exceed RTO of 4 hours
3. Environment must support SRM failover between Datacenter A and Datacenter B where an entire datacenter is lost

Assumptions

1.Three (3) vCenter servers will be used, One (1) at Datacenter A and Two (2) at Datacenter B
2. Environment has Two (2) Production clusters (One per Datacenter), and One (1) vCloud Cluster at Datacenter B each with a dedicated vCenter
3. Stretched clusters are not used
4. All vSphere Infrastructure servers (including SSO) are protected by SRM and vSphere HA
5. Inter-site Metropolitan Area Network is high bandwidth (>10Gb) , low latency (<5ms) and highly available (99.999%)
6. The average number of authentications per second for each SSO instance is <30 (Configuration Maximum)

Constraints

1. The environment uses traditional agent based backup solution which may not meet RPO/RTO requirements

Motivation

1. Future proof the environment

Architectural Decision

1. Use “Multi-site” SSO deployment mode
2. Do not use SSO “High Availability” clusters
3. The Primary SSO server will be at Datacenter B
4. The remaining vCenter servers will be “Secondaries” and point to the Datacenter B Primary SSO instance
5. The each SSO instance will be on a dedicated Windows 2008 x64 R2 instance
6. Each SSO instance will use the bundled SQL database
7. (Optional) For greater availability , vCenter Heartbeat will be used to protect each SSO instance

Justification

1. The environment is being designed (where) possible to sustain a Metropolitan Area Network failure between the two (2) datacenters

2. If “High Availability” mode is used, at least one (1) vCenter would be accessing SSO across the MAN link which introduces an unnecessary dependency on the MAN links

3. “High Availability” currently requires manual intervention which can be complicated and problematic

4. “Basic” mode prevents the use of Linked Mode which will make management of the environment more difficult

5. Using Multisite mode allows faster access to authentication services as each SSO instance is configured with Active Directory servers located at the same datacenter.

6. Multisite mode is required for the use of Linked-Mode and Linked Mode will  make day to day management easier

7. If one instance SSO goes offline for any reason, this will not impact production virtual machines. It will simply prevent any authentication to the affected vCenter server.

8. Having the SSO Primary at Datacenter B ensures only traffic from one vCenter (Datacenter A vCenter) traverses the MAN link as the third vCenter (for vCloud Director) is at Datacenter B

9. In the event of Datacenter B having a full datacenter wide failure for any reason, the Primary SSO instance being offline will not impact the management of Datacenter A OR the ability for the environment being recovered by SRM.

10. During an SSO upgrade, multiple vCenter’s cannot co-exist and using a centralized (or shared) SSO instance would overly complicate the upgrade process and lead to extended impact to the vSphere environments.

Alternatives

1. Use “Basic” Mode, resulting in a standalone version of SSO for each vCenter server

2. Use “High Availability Cluster” (Shared the same SSO database and identity sources) with one SSO server per physical datacenter

3. Use “Multisite” deployment with “High Availability Clusters” per datacenter

4. Host SSO database on a SQL Server

5. Run SSO on the vCenter server with or without the SSO database locally

6. Run a single SSO instance shared by all three (3) vCenters and use vCenter Heartbeat running across the MAN to protect SSO

Implications

1. Without a “High Availability Cluster” or SSO being protected by vCenter Heartbeat at each datacenter, the SSO for each site is a Single point of failure where authentication to the affected vCenter will fail

2. In the event of one (1) SSO server failing at Datacenter A, the SSO role does not failover to Datacenter B, or vice versa. In this case, All authentication requests on the site where SSO has failed, will fail.

3. Requires the installable version of SSO, which is Windows Only. The use of the vCenter Server Appliance (VCSA) is not available.

4. Additional Windows 2008 licenses are required for the SSO servers

Related Articles

1. Disabling Single Sign On – Dont Do It! – LongWhiteClouds

2. vSphere 5.1 Single Sign On (SSO) Configuration – Architectural Decision flowchart

I would like to Thank Michael Webster VCDX#66 (@vcdxnz001) for his contribution to this example architectural decision.

CloudXClogo