NCP-MCI-6.5 Questions and Answers

The issue described pertains to the inability to ping the IPMI IPs after moving the IPMI network links to the actual switches with specific VLAN configurations. The two changes that the administrator needs to make are:

A. SSH to AHV and set the VLAN ID using IPMI Tool: Since all VLANs are tagged in the new network configuration, the IPMI network interface needs to be aware of the VLAN it’s supposed to communicate on. This can be achieved by setting the VLAN ID using the IPMI Tool on the AHV.

C. SSH to AHV and change the IP address using IPMI tool: If the IPMI IP addresses were initially set in a different subnet that is not routable in the new network configuration, the administrator would need to change the IPMI IP addresses to match the new network configuration. This can be done by SSHing to the AHV and using the IPMI Tool to change the IP address.

Port 389 is the default port for LDAP without SSL encryption. Port 636 is used for LDAP over SSL (LDAPS). Port 3268 and 3269 are used for Global Catalog (GC) and Global Catalog over SSL (GCSSL), respectively2.

https://portal.nutanix.com/page/documents/details/?targetId=Web_Console_Guide-Prism_v4_7:lic_licensing_managing_c.html

Reclaiming Licenses (Including License Renewal)

You can reclaim and optionally re-apply licenses for nodes in your clusters:

• You must reclaim licenses when you plan to destroy a cluster. First reclaim the licenses, then destroy the cluster. You do not need to reclaim Starter licenses. These licenses are automatically applied whenever you create a cluster, including after you have destroyed a cluster.
• Return licenses to your inventory when you remove one or more nodes from a cluster. Also, if you move nodes from one cluster to another, first reclaim the licenses, move the nodes, then re-apply the licenses.
• You can reclaim licenses for nodes in your clusters in cases where you want to make modifications or downgrade licenses. For example, applying an Ultimate license to all nodes in a cluster where some nodes are currently licensed as Pro and some nodes are licensed as Ultimate. You might also want to transition nodes from Ultimate to Pro licensing.
• You must reclaim licenses when you renew licenses. First reclaim the expired licenses, then apply new licenses.

According to the Nutanix Support & Insights, in a two-node ROBO cluster with a witness VM, if one node goes down, the other node sends a leadership request to the witness VM and goes into single-node mode. The cluster remains available and can tolerate another failure of either the witness VM or the network link.

https://portal.nutanix.com/page/documents/details?targetId=Prism-Central-Guide-Prism-v5_10:mul-pc-install-scratch-c.html

 According to the Nutanix Support & Insights web search result4, Prism Central can be installed manually on an AHV cluster by using three disk images: boot, home, and data. These disk images must be downloaded from the portal for the Prism Central VM and uploaded to an image service on the AHV cluster. The boot image contains the operating system and kernel for Prism Central. The home image contains the configuration files and logs for Prism Central. The data image contains the database and application files for Prism Central.

According to the web search results, one possible cause of inter-VM communication failure between hosts is that the switch is not configured to allow VLAN 15 traffic. VLAN 15 is the default VLAN ID used by AHV for internal communication between CVMs and hosts. If the switch blocks or drops VLAN 15 packets, it will prevent inter-VM communication across hosts4. To enable full inter-VM communication, the administrator should update the switch to specifically allow VLAN 15 traffic on the ports connected to the AHV hosts.

According to the Dell Unity: Data Reduction Technical White Paper1, snapshots and clones on Dell Unity use the Copy-on-Write (CoW) algorithm to maximize efficiency and effectiveness. CoW is a technique that defers the copying of data until it is modified. This means that snapshots and clones only consume space when changes are made to the source or the clone, respectively. CoW also preserves the original data in case of a rollback or recovery operation.

The correct answer is C. The VLAN was not created on the upstream switches.

A VLAN (virtual local area network) is a logical segmentation of a physical network that allows devices on the same VLAN to communicate with each other, regardless of their physical location. A VLAN also isolates the devices on different VLANs from each other, unless there is a router or a layer 3 switch that can route traffic between VLANs. To create a VLAN, the administrator needs to configure the network devices that are involved in the VLAN, such as switches, routers, and hosts. The administrator also needs to assign a unique VLAN ID to each VLAN, which is a number between 1 and 4094 that identifies the VLAN1.

In Nutanix AHV, the administrator can create a Nutanix managed network with a specific VLAN ID for guest VMs. This network can be assigned to VM NICs using Prism Element or Prism Central. However, creating a Nutanix managed network does not automatically create the VLAN on the upstream switches that connect the AHV hosts. The administrator needs to manually configure the upstream switches to allow the VLAN traffic on the ports that connect to the AHV hosts. The administrator also needs to ensure that the upstream switches are interconnected physically or virtually and can forward traffic between different VLANs if needed2.

Therefore, if an administrator has created a Nutanix managed network with a VLAN ID of 512 and notices that the VMs on that network can only communicate with other VMs on the same host, but not with VMs on different hosts in the cluster, the most likely cause of this issue is that the VLAN was not created on the upstream switches. This means that the switches are dropping or blocking the traffic with VLAN ID 512 and preventing it from reaching other hosts or VMs. To resolve this issue, the administrator should create the VLAN on the upstream switches and allow it on the ports that connect to the AHV hosts3.

https://portal.nutanix.com/page/documen ts/details/?targetId=Prism-Central-Guide-Prism-v510:mul-alert-policies-user-defined-configure-pc-c.html

Curator is the process that runs on every node in a Nutanix cluster and is responsible for data management tasks such as deduplication, compression, erasure coding, and replication factor compliance. Curator also handles disk failure recovery by scanning Cassandra to find all data previously hosted on the failed disk, and all disks in that node. Curator then rebuilds the data on other nodes in the cluster using the distributed storage fabric1.

This is because Nutanix uses a distributed storage fabric (DSF) that replicates data across multiple nodes and drives to ensure data resiliency. When a drive fails, the cluster detects the failure and initiates a data rebuild process to restore the replication factor (RF) of the affected containers. The data rebuild process does not affect the availability or performance of the VMs, as they can still access their data from other replicas on other nodes or drives. Therefore, there is no need to wait for 60 minutes, use a shared volume group, or trigger an HA event.

Prism Element and NCC are two ways to run all NCC checks manually on a Nutanix cluster. Prism Element is the web console that provides management and monitoring capabilities for a single Nutanix cluster. Prism Element has a Health dashboard that shows the status of various components and services in the cluster, such as disks, nodes, CVMs, NCC, and alerts. The Health dashboard also allows the administrator to run NCC checks manually by using the Actions drop-down menu on the right side of the screen. The administrator can choose to run all NCC checks or specific checks based on the category or severity. The NCC checks will run in the background and generate a report that can be viewed or downloaded from the Summary tab. This method is easier and faster than running NCC from the command line on the CVM.

NCC stands for Nutanix Cluster Check, which is a framework of scripts that performs system checks and validations on Nutanix clusters. NCC can detect issues related to hardware, software, configuration, hypervisor, networking, and more. NCC can be run from the command line interface (CLI) of any CVM in the cluster by using the ncc command. To run all NCC checks manually, the administrator can use the command ncc health_checks run_all, which will execute all available checks and display the results on the screen. This method is more comprehensive and detailed than running NCC from Prism Element.

References: : [Health Dashboard - Prism Element Guide] : [Nutanix Cluster Check (NCC) - Nutanix Support & Insights] : [Running NCC Checks - Nutanix Support & Insights]

Flow Networking is a feature that enables software-defined networking for AHV clusters. It allows users to create and manage virtual private clouds (VPCs), subnets, and network services such as NAT, DHCP, routing, and VPN. Flow Networking also supports service insertion and chaining, which enables integration with third-party network functions such as firewalls and load balancers. Flow Networking is built on top of the microservices infrastructure (MSP) in Prism Central, which provides the platform for running various Nutanix services such as Calm, Karbon, and Objects. Therefore, to enable Flow Networking, the MSP must be enabled first on Prism Central1. The MSP can be enabled from the Prism Central settings page or from the command line interface (CLI) of the Prism Central VM2. Enabling the MSP will also enable Flow Microsegmentation, which is another feature that provides network security and visibility for AHV clusters.

The best way for the administrator to configure Prism to send encrypted messages to a set of recipients is to set the SMTP Security Mode to STARTTLS. This will ensure that all messages sent over SMTP are encrypted and secure. Additionally, the administrator should consider installing SSL certificates on Prism Central to ensure that the messages are being sent securely. Finally, the administrator should consider configuring Prism Central to use Cluster Lockdown, which will help ensure that the messages are only sent to the intended recipients.

According to the Nutanix Prism Element Guide, Prism Element uses a single SSL certificate on a Nutanix cluster. The certificate is used to secure the communication between the web browser and the Prism web console. The certificate is also used to authenticate the cluster to external services, such as Active Directory, SMTP, and SNMP. The certificate can be either self-signed or signed by a trusted certificate authority (CA). The certificate can be replaced or renewed through the Prism web console or the ncli command-line interface.

A native VLAN is a VLAN that is assigned to untagged traffic on a trunk port of a switch. A trunk port can carry traffic from multiple VLANs, but it needs to have a native VLAN to handle traffic that does not have a VLAN tag. The native VLAN is usually VLAN 1 by default on most switches, but it can be changed to any other VLAN number2. When creating a network profile on Nutanix, the administrator needs to specify the VLAN ID that matches the VLAN configuration on the physical switch. However, if the network profile uses the same VLAN ID as the native VLAN on the switch, it will cause network connectivity issues for the VMs connected to that network profile. This is because Nutanix AHV uses 802.1Q tagging for all network traffic, including traffic in the native VLAN. The switch will expect untagged traffic in the native VLAN and will drop any tagged traffic in that VLAN3. To fix this issue, the administrator needs to change the VLAN field from vlan. 1 to vlan. 0 in the network profile on Nutanix. This will tell Nutanix AHV to send untagged traffic for that network profile and match the native VLAN configuration on the switch4.

The best way to fix this issue is to increase the amount of memory assigned to the VM from the Prism web console. This option allows the administrator to modify the VM configuration without accessing the CVM or shutting down the VM. The Prism web console provides a simple and intuitive interface for managing Nutanix clusters and VMs1. To change the memory allocation for a VM, the administrator can follow these steps2:

• Go to the VM dashboard
• Select the VM from the VMs list
• Choose Update
• Adjust the amount of memory assigned to the VM
• Click Save

According to the Nutanix Volumes - Recommendations And Best Practices web search result3, two actions that the administrator should take when designing the Volume Group are:

• Distribute workload across multiple virtual disks: Use multiple disks rather than a single large disk for an application. Consider using a minimum of one disk per Nutanix node to distribute the workload across all nodes in a cluster. Multiple disks per Nutanix node may also improve an application’s performance. For performance-intensive environments, we recommend using between four and eight disks per CVM for a given workload.
• Enable RSS (Receive Side Scaling): Receive-side scaling (RSS) allows the system to use multiple CPUs for network activity. With RSS enabled, multiple CPU cores process network traffic, preventing a single CPU core from becoming a bottleneck. Enabling RSS within hosts can be beneficial for heavy iSCSI workloads. For VMs running in ESXi environments, RSS requires VMXNET3 VNICs. For Hyper-V environments, enable VMQ to take full advantage of Virtual RSS.

Automated live migration is a feature of Nutanix that allows the cluster to automatically move VMs from one host to another without any downtime, in order to optimize the performance and availability of the cluster. According to the Nutanix documentation1, automated live migration can occur in the following scenarios:

• Cluster resource hotspot: When a host or a group of hosts experience high resource utilization, such as CPU, memory, or network, the cluster can automatically migrate some VMs to other hosts with lower utilization, in order to balance the load and avoid performance degradation.
• AOS upgrade: When upgrading the Nutanix software (AOS), the cluster can automatically migrate the VMs from the host that is being upgraded to another host in the same availability zone, in order to maintain the VM availability and minimize the impact of the upgrade process.
• AHV host maintenance mode: When putting an AHV host into maintenance mode, the cluster can automatically migrate all the VMs from that host to another host in the same availability zone, in order to prepare the host for maintenance operations such as hardware replacement or firmware update.

According to the Nutanix Support & Insights, IPAM enables AHV to assign IP addresses automatically to VMs using DHCP. You can configure each virtual network and associated VLAN with a specific IP subnet, associated domain settings, and group of IP address pools available for assignment.

According to the web search results, two steps that should be taken to prepare for relocating an AHV cluster to a new datacenter during a maintenance window are:

• Shut down all user VMs in the cluster: This step is necessary to ensure that there is no data loss or corruption during the relocation process. The user VMs can be shut down either individually or in bulk by using the Prism Element web console or the acli command-line interface1.
• Stop all Nutanix Files clusters: If the AHV cluster hosts any Nutanix Files clusters, they should be stopped before relocating the cluster. Nutanix Files clusters are composed of one or more virtual machines that provide file services to clients. Stopping a Nutanix Files cluster will stop all the file server VMs and release the resources they consume2. The Nutanix Files clusters can be stopped by using the Prism Element web console or the ncli command-line interface3.

First Preference:

• Policy is applied to a specific entity

2nd Preference:

• Policy is applied to an entity type in a category

3rd Preference:

• Policy is applied to an entity type in a cluster

4th Preference:

• Policy is applied to all entities of an entity type

Comprehensive Detailed Explanation with References:In Nutanix Prism, when multiple alert policies are created and applied to the same entities, the policies are evaluated based on their specificity. The order of precedence from highest to lowest is as follows:

• Policy is applied to a specific entity: Custom alert policies that are applied to specific entities take precedence over those applied to broader categories. This is because the more specific policy is usually created with a particular context or requirement in mind for that entity.
• Policy is applied to an entity type in a category: The next level of precedence is given to policies that are applied to all entities of a certain type within a specific category. Categories allow grouping of entities based on certain criteria, and policies applied here are more specific than to an entire cluster or entity type.
• Policy is applied to an entity type in a cluster: This refers to policies that are applied to all entities of a certain type within a specific cluster. This is more general than the above two but still targets a specific cluster environment.
• Policy is applied to all entities of an entity type: The lowest precedence is given to policies that are broadly applied to all entities of a particular type across the entire Nutanix environment.

This order ensures that the most specifically targeted policies are given priority, which allows for fine-tuned control and customization of alert policies. The details of alert policy precedence are typically covered in the Nutanix Prism Central Guide and the documentation related to Prism Central's alerting and policies.

According to the How to use the cvm_shutdown script web search result3, the cvm_shutdown script signals HA when shutting down the CVM (Controller VM) to forward the storage traffic to another healthy CVM. Instead of using sudo shutdown or sudo reboot commands, this script should be used to minimize I/O hits in user VMs running on the present hypervisor host. The cvm_shutdown -P now command will initiate the shutdown process on the CVM immediately. Therefore, if the administrator needs to perform an orderly shutdown of the CVM, they should execute this command from the CVM.

Shadow Clones is a Nutanix feature that provides effective caching optimization in VDI environments. VDI stands for Virtual Desktop Infrastructure, which is a technology that allows users to access virtual desktops hosted on a centralized server. VDI environments typically have a high degree of similarity among desktop images, which means that many VMs access the same data blocks from the storage layer. Shadow Clones leverages this similarity by creating read-only copies of frequently accessed data blocks on each node’s SSD tier, reducing network traffic and improving performance. Shadow Clones works automatically and transparently without any configuration or intervention from the administrator.

References: : [Fault Tolerance - Nutanix Bible] : [Block Awareness - Nutanix Bible] : [Block Awareness - Nutanix Support & Insights] : [Shadow Clones - Nutanix Bible] : [Shadow Clones - Nutanix Support & Insights] : [Shadow Clones - Nutanix Community]

A Compute Only node is a node that does not have any local storage devices and only provides compute resources to the cluster2. A Compute Only node does not run a CVM, but instead relies on the CVMs of other nodes to access the distributed storage fabric2

network segmentation on Nutanix clusters refers to creating a separate network for service-specific communication and isolating different types of traffic over selected VLANs or physical interfaces.

https://next.nutanix.com/ncm-intelligent-operations-formerly-prism-pro-ultimate-26/network-segmentation-isolating-service-specific-traffic-39463

https://next.nutanix.com/how-it-works-22/network-segmentation-basics-38414

Prism Element is a graphical user interface that allows you to manage Nutanix clusters1. You can use Prism Element charts to understand Nutanix cluster workloads and troubleshoot performance related issues2.

memory optimized virtual machine sizes offer the best performance for SQL Server workloads on Azure VMs. Adding more RAM to the user VM can help reduce paging and improve query execution times.

SQL Server performance can be affected by disk latency and throughput. By creating separate virtual disks for data and logs, you can spread activity across multiple spindles and reduce disk contention.

https://next.nutanix.com/how-it-works-22/differences-between-prism-element-prism-central-and-prism-pro-37137

Nutanix provides two types of granular RBAC for AHV hosts: category based and cluster based3. Category based RBAC allows administrators to assign roles to users or groups based on categories, which are key-value pairs that can be applied to various entities in Prism Central, such as clusters, hosts, VMs, images, and networks. Categories can be used to group entities by different criteria, such as department, project, environment, or location. For example, an administrator can create a category key named Department and assign different values to it, such as Finance, Marketing, or Engineering. Then, the administrator can apply this category to different clusters or hosts and assign roles to users or groups based on this category. This way, users or groups can have different levels of access to different clusters or hosts depending on their department4.

Cluster based RBAC allows administrators to assign roles to users or groups based on specific clusters registered in Prism Central. For example, an administrator can create a role named Cluster Admin and assign it to a user or group for a particular cluster. This way, the user or group can have full access to that cluster and its hosts and VMs, but not to other clusters5.

According to the web search results, the policy that should be used to meet this requirement is an Isolation Environment Policy. An Isolation Environment Policy is a type of security policy that can be created in Prism Central using Flow Network Security, which is a feature that provides microsegmentation and network security for Nutanix environments1. An Isolation Environment Policy allows the administrator to isolate a group of VMs from another group of VMs based on their categories, and block all traffic between them regardless of direction2. This policy can be useful for creating isolated environments for testing, development, or compliance purposes2.

According to the Nutanix Prism Central Guide, to configure a syslog server in Prism Central, you need to specify the transport protocol (TCP or UDP) and the IP address/port of the syslog server.

According to the Nutanix Support & Insights web search result3, advertised capacity is an advanced container setting that allows the administrator to reserve an advertised storage space for a storage container. An advertised capacity setting gives the hypervisor a maximum storage size that the storage container can use. This setting can be any arbitrary value greater than or equal to the resiliency required. The hypervisor ensures that the storage container storage doesn’t go beyond the advertised capacity. If the administrator wants a container to be displayed and limited to 1TB in the hypervisor, they should set the advertised capacity to 1TB.

 When a node with Erasure Coding fails, the cluster will automatically rebuild the missing data using replication factor (RF) 2 or 3, depending on the cluster configuration. This means that the data that was previously stored using Erasure Coding will now be stored using full copies, which may increase the amount of data stored in the SSD tier1.

Nutanix leverages a method for determining the bands called ‘Generalized Extreme Studentized Deviate Test’. A simple way to think about this is similar to a confidence interval where the values are between the lower and upper limits established by the algorithm.

Another web source3 shows an example of how anomaly detection works in Nutanix Prism Central. In the video, you can see that when the observed value of a metric deviates significantly from the predicted value based on historical data, an anomaly event is triggered and displayed on a chart.

Therefore, by comparing the observed values with the predicted values based on historical data, Nutanix anomaly detection can identify abnormal behavior and alert you accordingly.

 According to the Nutanix Support & Insights web search result1, the name of the internal bridge used by AHV nodes and CVMs is br0. The internal bridge is an Open vSwitch (OVS) bridge that connects the AHV host management interface, the CVM interface, and the VM vNICs. The internal bridge also acts as a gateway for the CVM and VM traffic to reach the external network through the host physical NICs.

"Playbook allows you to define a trigger that results in the execution of an action or a series of actions. A trigger may be an event that occurs in the system, such as an alert or a request made by you. The resultant actions that you configure can be VM actions, communication actions, alert actions, or report actions." https://portal.nutanix.com/page/documents/details?targetId=Intelligent-Operations-Guide-vpc_2023_3:ssp-report-management-ssp-pc-c.html#:~:text=The%20environment%20summary%20report%20provides,is%20registered%20to%20Prism%20Central.

According to the web search results, a consistency group is a group of related applications or services that must be recovered together in order to work properly, and this means more than being recovered at the same time67. They also typically need to be recovered to the same point in time6. Therefore, to meet the requirement of protecting all VMs of a multi-tier application at the same time, the administrator must create a consistency group for the application and place all VMs in it8. This way, the administrator can apply data protection policies and schedules to the entire consistency group as a single unit8.

According to the web search results, the two actions that the administrator should perform to determine if the current cluster can accommodate the new VMs are:

• Utilize Optimize Resources for VM efficiency: Optimize Resources is a feature in Prism Central that helps the administrator improve the efficiency and performance of their VMs by identifying and resolving issues such as overprovisioning, inactivity, constraints, or bullying3. By using Optimize Resources, the administrator can reclaim unused resources and optimize the resource allocation for their VMs3.
• Determine utilization with Cluster Runway: Cluster Runway is a feature in Prism Central that helps the administrator estimate how long their cluster can continue to run normally based on the current consumption rate of CPU, memory, and storage resources4. By using Cluster Runway, the administrator can see how adding more VMs will affect the resource utilization and capacity of their cluster4.

A constrained VM is one that does not have enough resources for the demand and can lead to performance bottlenecks. A VM is considered constrained when it exhibits one or more of the following baseline values, based on the past 21 days: CPU usage > 90% (moderate), 95% (severe) CPU ready time > 5%, 10% Memory usage > 90%, 95% Memory swap rate > 0 Kbps1. To provide adequate host resources, resize (increase) the constrained VMs1.

According to the Migration to a different processor web search result2, live migration of VMs depends on the source and destination hosts having the same CPU functions (CPU flags). Live migration requires the source and destination hosts to have CPUs from the same manufacturer, and only CPU functions which both hosts support are provided (same CPU generation, or by using VMware Enhanced vMotion Compatibility (EVC)). If the administrator adds a node with older generation processors to an existing AHV cluster with newer generation processors, then live migration of VMs is prevented between newer and older processors, unless EVC is enabled.