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System Design
SREdle
⚡ 1420 ELO
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LOAD BALANCING
Load Balancing: Scale Horizontally
Visualization: 1. Placement: On-Premises vs Cloud VPCs
Internet
Users
IGW
Internet Gateway
Cloud LB
Public Subnet
App Node 1
AZ-A (Private)
App Node 2
AZ-B (Private)
Press enter or space to select a node. You can then use the arrow keys to move the node around. Press delete to remove it and escape to cancel.
Press enter or space to select an edge. You can then press delete to remove it or escape to cancel.
1. Placement: On-Premises vs Cloud VPCs
2. Layer 4 (Transport) vs Layer 7 (Application)
3. Load Balancing Algorithms
4. Health Checks & High Availability
5. Advanced SRE Load Balancing
DOWNLOADING CONCEPT: 1. PLACEMENT: ON-PREMISES VS CLOUD VPCS...
On-Premises
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Traditionally, Load Balancers are massive physical hardware appliances (like F5 BIG-IP or A10) sitting in the DMZ.
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They require manual firmware updates, rack space, and expensive licenses.
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If the hardware fails, you need a backup unit sitting idle (Active-Passive).
Public Cloud VPCs
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In AWS/GCP, Load Balancers are Software-Defined (e.g., AWS ALB/NLB).
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They exist in Public Subnets to receive internet traffic, while your actual Application Servers sit safely in Private Subnets with no public IPs.
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Cloud LBs automatically scale under the hood, routing traffic across multiple Availability Zones (AZs) for high availability.
▲ LIVE INCIDENT
Users are reporting random 502 Bad Gateway errors on 1 out of every 3 page loads.
sre@arena:~/load-balancing
sre@arena
:
~
$
curl -s http://internal-lb/health | grep status
▶ EXECUTE COMMAND