Does Azure provides redundancy or resiliency at Application Gateway level in the event of Application Gateway service or component getting crashed or stopped. Also if it is redundant or resilient then please elaborate how it is achieved.

Hi @Aniket Jagadale , Azure Application is a PaaS offering and when you deploy it, multiple instances of Application gateway will be deployed. And the traffic which you send to the Application gateway will be load balanced between those instances. So, it is highly available and redundant by default. Only when all the Application Gateway instance goes down at the same time (highly unlikely to happen) you have a problem and that can be resolved by deploying another Application gateway in another region and use Traffic Manager to load balance traffic between those Application Gateways to achieve 2 tier of redundancy. Hope this helps! Regards, Msrini

Redundancy at Application Gateway level

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msrini-MSFT 9,286 Reputation points Microsoft Employee

2021-11-03T04:39:44.12+00:00

Hi @Aniket Jagadale ,

Azure Application is a PaaS offering and when you deploy it, multiple instances of Application gateway will be deployed. And the traffic which you send to the Application gateway will be load balanced between those instances. So, it is highly available and redundant by default.

Only when all the Application Gateway instance goes down at the same time (highly unlikely to happen) you have a problem and that can be resolved by deploying another Application gateway in another region and use Traffic Manager to load balance traffic between those Application Gateways to achieve 2 tier of redundancy.

Hope this helps!

Regards,
Msrini
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Aniket Jagadale 41 Reputation points

2021-11-03T07:34:57.6+00:00

Hi Msrini,

Thanks for the answer but now I've one more query what will happen to the applications running on the application server behind the Application gateway in the event of Application Gateway instance getting crashed.

Also in case of Load balancers do we have it deploy another load balancer in separate region in the similar case like application gateway instance getting crashed and what will happen to the applications/services running on the backend pool.

One more query :-)

If any of the application servers or backend servers in the backend pool of Application Gateway or Load balancer gets disconnected or shuts down will the Application Gateway/Load balancer move to the next available appln server or backend server and what will happen to the applications running on the backend servers.

Regards,
Aniket.

msrini-MSFT 9,286 Reputation points Microsoft Employee

2021-11-03T08:46:46.62+00:00

If one of the Application gateway instance fails, that instance will be taken out of rotation. So the backend server is not affected.

For Load Balancer it is different. It is not a deployment like Application Gateway. It is part of infrastructure. Only cause of failure is the failure of the Public IP. So, in that case you need deploy another LB in another region. Again, here if the IP fails, then backend Applications will not receive any traffic. Hence, you need to have another LB in another region. But IP failure is highly unlikely to happen.

Yes, if you have a Traffic Manager, if one Application gateway;s backend servers are all gone, then AppGW will respond with 502 and TM will switch to another Application Gateway.

If you find the response useful, mark it as answer to help other community folks.

Aniket Jagadale 41 Reputation points

2021-11-03T09:50:42.63+00:00

Thanks Msrini
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Redundancy at Application Gateway level

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