Azure Interview Questions Part #6

Questions

Q #1 How could you reserve the IPs in Azure public and private if you can ?

Q #2 What are the different types of Load Balancers provided by Azure and talk about there usage as regional and Global.

Q #3 How many IPs are reserved in a private subnet or how many are usable if for subnet 10.0.1.0/24.

Q #4 Can I replicate the ON-prem VM’s over a site to site VPN to azure if No then Why ?

Q #5 If i replicate to Azure via ASR , what kind of storage account or managed disk do i need ?

Q #6 Can I exclude specific disks from replication of on-prem machines to azure via ASR if yes then how ?

Q #7  Can i throttle the bandwidth allotted for replication traffic ?

Q #8 How can i access the Azure VM after fail-over or what all preparation needed ?

Q #9 If i am replicating between 2 data centers what happens if my primary datacenter experienced an unexpected outage ?

Q #10 What all permissions needed for successful replication and failover via ASR ?




Lets check the Answers :)

Q -> How could you reserve the IPs in Azure public and private if you can ?

Yes you can for public IP you can have Public IP Prefix if you want to use , You can also create Static Public IP. For private IP there are 5 reserved IP already first 4 and last IP apart from these you can save by creating NIC and assigning IPs to it.

Q-> What are the different types of Load Balancers provided by Azure and talk about there usage as regional and Global.

Azure provides 5 Load balancers :

3 Regional – Basic LB, Standard LB and Application Gateway.

2 Global – Traffic manager & Front Door.

For regional non-http or non-https traffic or if you want load balancing on L-4 you can choose Basic or Standard LB or If you want to load balanced on Application layer or http and https then App gateway which also provide other features like WAF, SSL offload, Path based routing.

For global if you want not necessary http or https  type traffic or DNS based load balancing then Traffic manager But for L-7 global point of presence you need Front Door.

https://www.youtube.com/watch?v=ypwgU2bKkB4&t=382s

https://docs.microsoft.com/en-us/azure/architecture/guide/technology-choices/load-balancing-overview

Q  How many IPs are reserved in a private subnet or how many are usable if for subnet 10.0.1.0/24.

Azure reserves 5 IP addresses within each subnet. These are x.x.x.0-x.x.x.3 and the last address of the subnet. x.x.x.1-x.x.x.3 is reserved in each subnet for Azure services.

x.x.x.0: Network address

x.x.x.1: Reserved by Azure for the default gateway

x.x.x.2, x.x.x.3: Reserved by Azure to map the Azure DNS IPs to the VNet space

x.x.x.255: Network broadcast address.

In case of 10.0.1.0/24 we have only 251 ips to use where first IP will be x.x.x.4 and last x.x.x.255

Q  Can I replicate the ON-prem VM’s over a site to site VPN to azure if NO then Why ?

No We cant replicate over Site to Site because replication traffic reaches the public endpoints of an Azure Storage. Thus you can only replicate over the public internet or via ExpressRoute that too Public/MS peering.

Q If I replicate to Azure, what kind of storage account or managed disk do I need ?

You need an LRS or GRS storage. We recommend GRS so that data is resilient if a regional outage occurs, or if the primary region can't be recovered. The account must be in the same region as the Recovery Services vault. Managed disks only support LRS.

Q Can I exclude specific disks from replication of on-prem machine to Azure via ASR if yes then how?

Yes you can during enable replication step you can uncheck the disk that you don’t want to replicate.

Q Can I throttle bandwidth allotted for replication traffic?                                                                                                                                                                  Yes that can be done from Config server. On config server desktop we have Azure Backup shortcut , we need to open it and go to the change properties from where we can enable the throttling.

Q How do you access the Azure VM after fail-over or what all preparation is needed ?                                                                                                                    You can access over internet, Site to Site connection, express route or Azure bastion. You need to take care of RDP port in NSG.

https://docs.microsoft.com/en-us/azure/site-recovery/site-recovery-test-failover-to-azure#prepare-to-connect-to-azure-vms-after-failover

Q If I'm replicating between two datacenters what happens if my primary datacenter experiences an unexpected outage?                                                  You can trigger an unplanned failover from the secondary site. Site Recovery doesn't need connectivity from the primary site to perform the failover.

Q What permissions needed for successful replication and failover via ASR

Usually Administrator does that who has all the permissions or contributor atleast however to be precise you need permissions to take below actions –

·        Permission to create a virtual machine in the selected resource group

·        Permission to create a virtual machine in the selected virtual network

·        Permission to write to the selected Storage account

https://docs.microsoft.com/en-us/azure/site-recovery/site-recovery-role-based-linked-access-control#permissions-required-to-enable-replication-for-new-virtual-machines