GCP Load Balancing and Autoscaling

Managed instance groups and unhealthy instances...

Managed instance groups can automatically identify and recreate unhealthy instances in a group to ensure that all the instances are running optimally.

Instance group of a backend...

May be a managed instance group with or without autoscaling or an unmanaged instance group.

SSL proxy traffic between the proxy and backend...

Can be either SSL (recommended) or TCP.

Global Cloud Load Balancing leverages...

Google frontends, which are software-defined, distributed systems that sit in Google's points of presence and are distributed globally.

What URL maps are for...

You can configure URL maps that route some URLs to one set of instances and route other URLs to other instances.

Updating managed instance groups

You can easily update all the instances in the group by specifying a new template in a rolling update.

Target pool resource is...

Target pool resource defines a group of instances that receive incoming traffic from forwarding rules.

Categories of Cloud Load Balancing (2)

- Global. - Regional.

What protocols global Cloud Load Balancing can handle

- HTTP(S). - SSL proxy. - TCP proxy.

Backend service contains...

- Health check. - Session affinity. - Timeout setting. - One or more backends.

Example of capacity setting usage

- If you want your instances to operate at a maximum of 80% CPU utilization, you would set your balancing mode to 80% CPU utilization and your capacity to 100%. - If you want to cut instance utilization in half, you could leave the balancing mode at 80% CPU utilization and set capacity to 50%.

If an instance in a managed instance group stops, crashes is deleted not through instance group commands...

- Instance group automatically recreates the instance so it can resume its processing tasks. - Recreated instance uses the same name and the same instance template as the previous instance.

Backend of backend service consists of...

- Instance group. - Balancing mode. - Capacity scaler.

Backends of a network load balancer can be...

- Instance group. - Target pool.

Benefits of SSL proxy load balancing...

- Intelligent routing. - Certificate management. - Security patching. - SSL policies.

Benefits of TCP proxy load balancing...

- Intelligent routing. - Security patching.

Internal load balancing IP addresses

- Internal load balancer enables you to run and scale your services behind a private load balancing IP address. - This means that it is only accessible through the internal IP addresses of virtual machine instances that are in the same region.

Types of Regional Load Balancers

- Internal load balancers. - Network load balancers.

What is to define for health check...

- Protocol. - Port. - Health criteria.

Network load balancing...

- Regional, non-proxied load balancing service. - All traffic is passed through the load balancer, instead of being proxied. - Traffic can only be balanced between VM instances that are in the same region, unlike a global load balancer.

Internal load balancing is...

- Regional, private load balancing service for TCP- and UDP-based traffic. - HTTP(S) support in Beta.

Steps to configure a managed instance group... (5)

- Single or multi-zoned, and where those locations will be. - Ports for load balancing. - Instance template. - Autoscale configuration - Create a health.

Protocols supported by network load balancing

- UDP. - TCP/SSL ports.

Managed instance groups is...

Collection of identical VM instances that you control as a single entity, using an instance template.

Network load balancers use...

Maglev, which is a large, distributed software system.

Regional and zonal managed instance groups...

Regional are preferable: they protect against zonal failures and unforeseen scenarios where an entire group of instances in a single zone malfunctions

Balancing mode of a backend...

- Tells the load balancing system how to determine when the backend is at full usage. - If all the backends for the backend service in a region are at full usage, new requests are automatically routed to the nearest region that can still handle requests. - Balancing mode can be based on CPU utilization or requests per second (RPS).

Target use for internal load balancing

- Use internal load balancing to configure an internal load balancing IP address to act as the frontend to your private backend instances. - Because you don't need a public IP address for your load-balanced service, your internal client requests stay internal to your VPC network and region.

When to use Global Cloud Load Balancing

- When your users and instances are globally distributed. - Your users need access to the same applications and content. - You want to provide access using a single anycast IP address.

HTTP(S) load balancing characteristics... (8)

- Works globally. - Provides anycast IP address. - HTTP or port 80 or 8080. - HTTPs on port 443. - IPv4 or IPv6 . - Autoscaling. - Enables content-based and cross-region load balancing. - URL maps.

Default timeout setting for a backend service

30 sec

QUIC protocol...

Transport layer protocol that allows faster client connection initiation, eliminates head-of-line blocking in multiplexed streams, and supports connection migration when a client's IP address changes.

How many SSL certificates could be configured for target proxy?

Up to 10.

How HTTP(S) load balancing works...

- A global forwarding rule directs incoming requests from the internet to a target HTTP proxy. - The target HTTP proxy checks each request against a URL map to determine the appropriate backend service for the request. - The backend service directs each request to an appropriate backend based on serving capacity, zone, and instance health of its attached backends.

What is anycast IP address

- Anycast, also known as IP anycast, is a networking technique that allows for multiple machines to share the same IP address. - Based on the location of the user request, the routers send it to the machine in the network that is closest.

Autoscaling policy can be based on...

- CPU utilization. - Load balancing capacity. - Monitoring metrics. - Queue-based workload.

How long it takes for changes to backend services to come in effect?

- Changes are not instantaneous. - It takes several minutes to propagate.

Steps to create a managed instance group...

- Create an instance template. - Create a managed instance group of n specified instances. - Instance group manager automatically populates the instance group based on the instance template.

Managed instance groups

- Deploy identical instances based on instance template. - Instance group can be resized. - Manager ensures all instances are RUNNING. - Typically used with autoscaler. - Can be single zone or regional.

Cloud Load Balancing gives you the ability...

- Distribute load-balanced compute resources in single or multiple regions to meet your high availability requirements. - Put your resources behind a single anycast IP address. - Scale your resources up or down with intelligent autoscaling.

Target pool characteristics...

- Forwarding rules only for TCP and UDP traffic. - Up to 50 target pools per project. - One health check per pool. - Instances must be in the same region.

SSL proxy certificate management...

- From a certificate management perspective, you only need to update your customer-facing certificate in one place when you need to switch certificates. - Also, you can reduce the management overhead for your virtual machine instances by using self-signed certificates on your instances.

What is Cloud Load Balancing?

- Fully distributed. - Software-defined. - Managed service. - It is not instance or device-based, so you do not need to manage a physical load balancing infrastructure.

SSL proxy load balancing...

- Global load balancing for encrypted, non-HTTP traffic. - Terminates SSL session at load balancing layer. - IPv4 or IPv6 addresses for client traffic.

TCP proxy load balancing

- Global load balancing for unencrypted, non-HTTP traffic. - Terminates TCP sessions at load balancing layer. - IPv4 or IPv6 clients.

What to consider while choosing load balancing

- Global versus regional load balancing. - External versus internal load balancing. - Traffic type.

Load balancing that supports IPv6 addresses

- HTTP(S), - SSL proxy. - TCP proxy.

HTTPS load balancing

- HTTPS load balancer uses a target HTTPS proxy instead of a target HTTP proxy. - HTTPS load balancer requires at least one signed SSL certificate installed on the target HTTPS proxy for the load balancer. - The client SSL session terminates at the load balancer. - HTTPS load balancers support the QUIC transport layer protocol.

Internal HTTP(S) load balancer...

- It's in beta. - Proxy-based, regional Layer 7 load balancer that enables you to run and scale your services behind a private load balancing IP address that is accessible only in the load balancer's region in your VPC network.

Types of load balancing that are regional

- Network. - Internal.

What is backend service session affinity for...

- Normally, HTTP(S) load balancing uses a round-robin algorithm to distribute requests among available instances. - Session affinity attempts to send all requests from the same client to the same virtual machine instance.

Capacity setting of a backend...

Additional control that interacts with the balancing mode setting.

Internal load balancers use...

Andromeda, which is GCP's software-defined network virtualization stack.

SSL proxy security patching...

If vulnerabilities arise in the SSL or TCP stack, GCP will apply patches at the load balancer automatically in order to keep your instances safe.

SSL proxy intelligent routing...

Intelligent routing means that this load balances can route requests to backend locations where there is capacity.