How can administrators balance traffic load between multiple instances of an application?

How can administrators balance traffic load between multiple instances of an application?

• A. By using DNS policy
• B. By configuring a firewall
• C. By applying traffic shaping at the network edge
• D. By using a reverse proxy

Answer: (A)

Distributing traffic across several app instances can be done by controlling what IPs are returned when clients look up the service. DNS policy does this at the very first step of a connection: a DNS server can be configured to respond with multiple IP addresses for the service, so different clients (or successive lookups) end up contacting different instances. Using round‑robin or weighted DNS records, along with TTL settings, spreads the load across the available servers as soon as a client resolves the domain name. This approach has practical advantages: it’s simple to set up, requires no special load‑balancing hardware or software, and scales without adding extra layers. But it also has limits: caching across clients and intermediate resolvers means some users stick to one IP for longer than desirable, and DNS alone doesn’t automatically remove unhealthy instances or adapt to real-time load. If an instance fails, some requests may still go to it until caches refresh. For dynamic health checks and immediate failover, more active load‑balancing methods (like a reverse proxy or dedicated load balancer) are typically used, but DNS policy remains a valid, low‑overhead way to achieve basic distribution across multiple instances.

Distributing traffic across several app instances can be done by controlling what IPs are returned when clients look up the service. DNS policy does this at the very first step of a connection: a DNS server can be configured to respond with multiple IP addresses for the service, so different clients (or successive lookups) end up contacting different instances. Using round‑robin or weighted DNS records, along with TTL settings, spreads the load across the available servers as soon as a client resolves the domain name.

This approach has practical advantages: it’s simple to set up, requires no special load‑balancing hardware or software, and scales without adding extra layers. But it also has limits: caching across clients and intermediate resolvers means some users stick to one IP for longer than desirable, and DNS alone doesn’t automatically remove unhealthy instances or adapt to real-time load. If an instance fails, some requests may still go to it until caches refresh. For dynamic health checks and immediate failover, more active load‑balancing methods (like a reverse proxy or dedicated load balancer) are typically used, but DNS policy remains a valid, low‑overhead way to achieve basic distribution across multiple instances.