Tag Archives: HA

Configuring vCenter 6.7 High Availability

The vCenter Server Appliance has provided vCenter High Availability (HA) with vSphere 6.5 onwards. In the fully functioning HTML5 release of vCenter 6.7 Update 1 onwards the setup of vCenter HA was hugely simplified. Read more about the improvements made in vSphere 6.7U1 in this blog post. By implementing vCenter HA you can protect your vCenter from host and hardware failures, and significantly reduce down time during patching due to the active / standby nature of the vCenter cluster.

The vCenter HA architecture is made up of the components in the vSphere image below. The vCenter Server Appliance is cloned out to create passive and witness nodes. Updated data is replicated between the active and passive nodes. In the event of an outage to the active vCenter the passive vCenter automatically assumes the active role and identity. Management connections still route to the same IP address and FQDN, however they have now failed over to the replica node. When the outage is resolved and the vCenter that failed comes back online; it then takes on the role of the passive node, and receives replication data from the active vCenter Server.

vCenter_HA

Requirements

  • vCenter HA was introduced with the vCenter Server Appliance 6.5
  • The vCenter deployment size should be at least small, and therefore 4 vCPU 16 GB RAM
  • A minimum of three hosts
  • The hosts should be running at least ESXi 5.5
  • The management network should be configured with a static IP address and reachable FQDN
  • SSH should be enabled on the VCSA
  • A port group for the HA network is required on each ESXi host
  • The HA network must be on a different subnet to the management network
  • Network latency between the nodes must be less than 10ms
  • vCenter HA is compatible with both embedded deployment model and external PSC
  • For further information on vCenter HA performance and best practises see this post

If you are configuring vCenter HA on a version of vCenter prior to 6.7 Update 1 then see this post. If you are configuring vCenter HA in a cluster with less than the required number of physical hosts, such as in a home lab, you can add a parameter to override the anti-affinity setting; see this post by William Lam.

Configuring vCenter HA

Log into the vSphere client and select the top level vCenter Server in the inventory. Click the Configure tab and vCenter HA. The vCenter HA summary page is displayed with a list of prerequisites, ensure these are met along with the requirements above. Click Setup vCenter HA.

vCenter_HA_1

Select the vCenter HA network by clicking Browse. Scroll down the vCenter HA resource settings, review the network and resource settings of the active node of the vCenter Server. Scroll down to the passive node and click Edit. Follow the on-screen prompts to select a folder location, compute and storage resources. Select the management and HA networks for the passive node, review the settings once complete and click Finish. Follow the same steps for the witness node.

vCenter_HA_2

On the IP settings page enter the HA network settings for the active, passive, and witness nodes. Click Finish.

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The vCenter Server will now be cloned and the HA network settings applied, this can be monitored from the tasks pane. Once complete the vCenter HA state will show Healthy, and all nodes in the cluster will show Up.

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You can edit the status of vCenter HA at any time by going back into the vCenter HA menu and clicking Edit. You also have the option of removing the vCenter HA configuration or manually initiating a failover.

vCenter_HA_Edit

For more information on vCenter 6.7 High Availability see the vCenter Documentation Centre here.

vRealize Operations High Availability

Following on from the vRealize Operations 6.4 Install Guide this post will detail High Availability (HA) for vRealize Operations Manager. By implementing HA the analytics cluster is protected against the loss of a single node. For example should the master node fail, services will automatically fail over to the replica node within 2-3 minutes. Following a fail over the cluster runs in degraded mode, and cannot tolerate the loss of another node until the cluster is returned to HA mode through repairing or replacing the failed node, or removing it if sufficient nodes exist within the cluster. The analytics cluster is made up of the master node, replica node, and data node or nodes. It does not include any remote collector nodes.

Requirements

  • There should be sufficient hosts in the vSphere cluster to have no more than one node running on each host. HA does not protect against the loss of more than one node, only one replica node can be configured.
  • Each node in the analytics cluster requires a static IP address.
  • When adding additional nodes keep in mind the following:
    • All nodes must be running the same version
    • All nodes must use the same deployment type, i.e. virtual appliance, Windows, or Linux.
    • All nodes must be sized the same in terms of CPU, memory, and disk.
    • Nodes can be in different vSphere clusters, but must be in the same physical location and subnet.
    • Time must be synchronised across all nodes.
    • Click here to see a full list of multiple node cluster requirements.
  • Note that for existing clusters the master node must be online to enable HA, and the cluster is restarted. This does not apply to new clusters where the cluster has not yet been started.

Deploy the Data Node

In order to configure HA a data node must be deployed and then converted into a replica node. The replica node holds a copy of all data stored in the master node. First let’s deploy our new node; download vRealize Operations Manager here.

Navigate to the vSphere web client home page, click vRealize Operations Manager and select Deploy vRealize Operations Manager.

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The OVF template wizard will open. Browse to the location of the OVA file and click Next.

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Enter a name for the virtual appliance, and select a location. Click Next.

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Select the host or cluster compute resources for the virtual appliance and click Next. Remember this should be on a different host to the master node.

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Review the details of the OVA, click Next.

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Accept the EULA and click Next.

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Select the same configuration size as the master node and click Next.

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Select the storage for the virtual appliance, click Next. For HA you should use a different datastore to the master node.

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Select the network for the virtual appliance, click Next.

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Configure the virtual appliance network settings, click Next. Click Finish on the final screen to begin deploying the virtual appliance.

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Configure the Replica Node

Once the virtual appliance has been deployed and is powered on, open a web browser to the FQDN or IP address configured during deployment. Select Expand Existing Installation.

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Click Next to begin the setup wizard.

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Enter the name of the new node, ensure Data is selected as the node type. Enter the IP address or FQDN of the master node and click Validate. Tick Accept this certificate and click Next to continue.

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Enter the admin password of the master node and click Next.

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Click Finish.

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Cluster Configuration

You will now be returned to the cluster admin page. Note the Waiting to finish cluster expansion. Installation in progress… message; the new node is being configured and will likely take 5-10 minutes. If you want to add any additional data nodes or remote collector nodes you can repeat the process above. For the purposes of this post we are adding a single data node to be converted to a replica. When you’re ready click Finish Adding New Node(s) and Ok to continue.

finish

Once the node to be used as a replica is online we can configure HA. Locate the High Availability section at the top right of the admin page, the status will be set to disabled, click Enable. Ensure the correct data node is selected to be converted to a replica node. Tick Enable High Availability for this cluster and click Ok.

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Configuring HA can take up to 20 minutes and the cluster will restart. Click Yes to continue.

confirm

You may need to log back into the admin console. The admin console for vRealize Operations Manager can be accessed by browsing to http://<vROps>/admin where <vROps> is the IP address of FQDN of your vRealize Operations Manager appliance or server. The HA status will now show enabled and the cluster online. Note that the role of the node has now changed to Master Replica.

The same data can now be accessed via both the master node and the replica node. Consider implementing load balancing for larger environments; review the vRealize Operations Manager Load Balancing document.

DRS Anti-Affinity

The final step is to configure an anti-affinity rule to stop the master and replica nodes (and any data nodes) from running on the same hosts. Log into the vSphere web client and browse to Hosts and Clusters. Click the vSphere cluster and select the Manage tab. Under Configuration click VM/Host Rules. Under VM/Host Rules click Add.

Enter a name for the rule, such as vRealize Operations Nodes, ensure Enable rule is ticked and select Separate Virtual Machines as the rule type. Click Add and select the vRealize Operations nodes. Click Ok.

drs

This rule will ensure DRS does not place nodes on the same hosts in a vSphere cluster.

Configuring vCenter 6.5 High Availability

The vCenter Server Appliance now provides vCenter High Availability (HA) with vSphere 6.5 onwards. By implementing vCenter HA you can protect your vCenter from host and hardware failures, and significantly reduce down time during patching due to the active / standby nature of the vCenter cluster. In vSphere 6.7 Update 1 onwards the vCenter HA configuration is simplified, see Configuring vCenter 6.7 High Availability for more information.

The vCenter HA architecture is made up of the components in the vSphere image below. The vCenter Server Appliance is cloned out to create passive and witness nodes. Updated data is replicated between the active and passive nodes. In the event of an outage to the active vCenter the passive vCenter automatically assumes the active role and identity. Management connections still route to the same IP address and FQDN, however they have now failed over to the replica node. When the outage is resolved and the vCenter that failed comes back online; it then takes on the role of the passive node, and receives replication data from the active vCenter Server.

vCenter_HA_1

Altaro-Free-VMware-ebook-Mastering-vSphere-468x60

Requirements

  • vCenter HA was introduced with the vCenter Server Appliance 6.5
  • The vCenter deployment size should be at least small, and therefore 4 vCPU 16 GB RAM
  • A minimum of three hosts
  • The hosts should be running at least ESXi 5.5
  • The management network should be configured with a static IP address and reachable FQDN
  • SSH should be enabled on the VCSA
  • A port group for the HA network is required on each ESXi host
  • The HA network must be on a different subnet to the management network
  • Network latency between the nodes must be less than 10ms
  • vCenter HA is compatible with both embedded deployment model and external PSC
  • For further information on vCenter HA performance and best practises see this post

Configuration Types

When setting up vCenter HA we are given the option of basic configuration or advanced. The correct deployment type depends on your environment. If the VCSA is managing its own ESXi host and virtual machine, or is managed by another vCenter Server in the same SSO domain then the basic deployment method should be used. This automatically clones the vCenter, and creates DRS anti-affinity rules.

If the VCSA is on a separate vCenter in a different SSO domain then the advanced deployment method should be used. In this case we need to manually add an additional NIC and clone the VCSA. The basic and advanced configuration types produce the same end result, but with a different process for different environments.

Both the embedded PSC and external PSC deployment models are supported. In this post we will walk through the advanced and basic configuration steps for vCenter with embedded PSC. For external PSC a load balancer can be implemented to provide HA, you can read more about implementing vCenter HA with the external deployment model here. If you are configuring vCenter HA in a cluster with less than the required number of physical hosts, such as in a home lab, you can add a parameter to override the anti-affinity setting; see this post by William Lam.

Basic Configuration Process

Log into the vSphere web client. Right click the top level vCenter Server in the inventory and select vCenter HA Settings. Click Configure in the top right hand corner.

ha1

Select the configuration type, in this example we are going to use Basic. Click Next.

basic1

An additional NIC will automatically be added to the active VCSA. Select the HA network to use and enter an IP address, remember this must be a separate subnet to the management network or the configuration wizard will error. Click Next.

basic2

Once the configuration wizard is complete the active VCSA will be cloned to create passive, and witness nodes. On this page we need to specify the HA IP addresses to use for each node, then click Next. You do not need to manually add any NICs during the basic configuration, this is all done for you. However as per the pre-requisites you do need to make sure a network is available to use for HA traffic.

basic3

Review the deployment page, if applicable you may need to change the compute or datastore locations by clicking Edit to ensure each component is spread across the vSphere cluster.

basic4

As you can see on the final page clone tasks will automatically be created. The new VMs are named VCSA-peer and VCSA-witness, where VCSA is the VM name of your current vCenter Server Appliance. Click Finish.

basic5

Monitor the tasks pane, vCenter HA may take around 5 minutes to clone and deploy the cluster nodes, depending on the speed of your underlying infrastructure. Once complete the vCenter HA status will show Enabled, and all nodes in the cluster will show Up.

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You can edit the status of vCenter HA at any time by going back into the vCenter HA menu and clicking Edit. These are the available options.

edit

Advanced Configuration Process

The advanced deployment process takes longer as it involves much more manual configuration. The first thing we need to do is add an additional network adapter to our existing vCenter Server Appliance, and configure a vCenter HA IP address. Log into the vSphere web client of the vCenter managing the VCSA. Locate and right click the VCSA, select Edit Settings. From the New device drop down select Network and click Add. Select the port group to use, remember this needs to be a separate subnet to the management network, ensure Connect is ticked and click Ok.

Now we can configure the network settings using the Appliance Management portal. Browse to https:// :5480 where is the IP address or FQDN of your vCenter Server Appliance. Log in with the root password.

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Select Networking on the left hand navigation menu.

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Open the Manage tab and click Edit next to the Networking Interfaces box. Expand nic1, note that the status is down, configure the IP settings and click Ok.

ip

Verify that nic1 is now showing a status of Up.

interfaces

We can now start the vCenter HA configuration wizard. Open the vSphere web client of the VCSA for which you want to configure HA. Right click the top level vCenter Server in the inventory and select vCenter HA Settings. Click Configure in the top right hand corner.

ha1

Select the configuration type, in this example we are going to use Advanced. Click Next.

advanced1

Enter the IP address settings for the passive and witness nodes, on the HA network, then click Next.

advanced2

Now we need to do some manual cloning, go back to the vSphere client of the vCenter Server managing the VCSA. Locate the VCSA in the inventory, right click and select Clone, Clone to Virtual Machine.

Run through the clone wizard, let’s create the passive node first. During the clone wizard we configure all settings, including management IP address and host name, to be the same as the active VCSA except for the HA IP address. Each node has a unique IP address on the HA network.

  • Enter a name and location for the virtual appliance.
  • Select different compute resource and datastores to the active VCSA if possible.
  • On the clone options page select Customise the operating system, Power on virtual machine after creation.

clone1

  • On the customise guest OS page click the create new specification icon.
  • Enter a name and description for the new customisation.

clone2

  • Enter the same OS host name and domain as the active node.
  • Configure the same time zone as the active node.
  • On the network page edit the settings for NIC1, select use the following IP settings, and enter the management network settings of the active vcsa. This network adapter will be used to assume the identity of the active VCSA in the event of a fail over.

nic1

  • Edit the settings for NIC2, select prompt the user for an address when the specification is used. Enter the subnet mask and leave the gateway blank. This adapter will be used for the HA network, we will configure the unique IP address shortly.

nic2

  • On the DNS and domain settings page of the wizard enter the domain name and DNS server(s) that the interface will connect to, click Finish.
  • You will be returned to the clone virtual machine wizard. Select the newly created customisation profile.
  • Enter the IP address for NIC1. This is the HA IP for the passive node we input during the vCenter HA configuration wizard earlier.

usersettings

  • Accept the default virtual hardware and vApp properties.

The VCSA will now be cloned to create the passive node. Repeat the steps above for the witness node, however this time select the existing guest customisation that we created first time round.

customisation

Enter the unique HA IP address for the witness node that we specified during the vCenter HA configuration wizard.

usersettings

When these manual steps have been completed go back to the vCenter HA configuration wizard and click Finish. Monitor the Configure a vCenter HA Cluster task in the recent tasks pane.

clone

Once complete the vCenter HA status will show Enabled, and all nodes in the cluster will show Up.

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For more information on vCenter HA or configuring different aspects of the advanced deployment; see the vCenter High Availability section of the vSphere 6.5 Documentation Centre.

The final step is to configure an anti-affinity rule to stop the vCenter Server appliances from running on the same hosts. Log into the vSphere web client and browse to Hosts and Clusters. Click the vSphere cluster and select the Manage tab. Under Configuration click VM/Host Rules. Under VM/Host Rules click Add.

Enter a name for the rule, such as vCenter HA, ensure Enable rule is ticked and select Separate Virtual Machines as the rule type. Click Add and select the vCenter Server nodes. Click Ok.

drs

This rule will ensure DRS does not place nodes on the same hosts in a vSphere cluster.