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Improve performance and reliability

Now that rate limiting is set up, your login page is now protected against credential brute for attacks.

In this tutorial, you will add a second origin for some basic round robining, and then use the Cloudflare Load Balancing product to fail traffic over as needed. You will also enhance your load balancing configuration through the use of "geo steering" to serve results from an origin server that is geographically closest to your end users.

1. Add another DNS record for www

To get started, add a DNS record for a second web server, which is located in Asia. The IP address for this server is 198.51.100.15.

$ git checkout -b step5-loadbalance
Switched to a new branch 'step5-loadbalance'
$ cat >> cloudflare.tf <<'EOF'
resource "cloudflare_record" "www-asia" {
zone_id = var.zone_id
name = "www"
value = "198.51.100.15"
type = "A"
proxied = true
}
EOF

Note that while the name of the resource is different because Terraform resources of the same type must be uniquely named, the DNS name, or what your customers will type in their browser, is the same: www.

2. Preview and merge the changes

Check the terraform plan and then merge and apply the changes.

$ terraform plan | grep -v "<computed>"
Refreshing Terraform state in-memory prior to plan...
The refreshed state will be used to calculate this plan, but will not be
persisted to local or remote state storage.
cloudflare_record.www: Refreshing state... (ID: c38d3103767284e7cd14d5dad3ab8669)
cloudflare_zone_settings_override.example-com-settings: Refreshing state... (ID: e2e6491340be87a3726f91fc4148b126)
cloudflare_rate_limit.login-limit: Refreshing state... (ID: 8d518c5d6e63406a9466d83cb8675bb6)
------------------------------------------------------------------------
An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
+ create
Terraform will perform the following actions:
+ cloudflare_record.www-asia
zone_id: "e097e1136dc79bc1149e32a8a6bde5ef"
name: "www"
proxied: "true"
type: "A"
value: "198.51.100.15"
Plan: 1 to add, 0 to change, 0 to destroy.
------------------------------------------------------------------------
Note: You didn't specify an "-out" parameter to save this plan, so Terraform
can't guarantee that exactly these actions will be performed if
"terraform apply" is subsequently run.
$ git add cloudflare.tf
$ git commit -m "Step 5 - Add additional 'www' DNS record for Asia data center."
[step5-loadbalance 6761a4f] Step 5 - Add additional 'www' DNS record for Asia data center.
1 file changed, 7 insertions(+)
$ git checkout master
Switched to branch 'master'
$ git merge step5-loadbalance
Updating e1c38cf..6761a4f
Fast-forward
cloudflare.tf | 7 +++++++
1 file changed, 7 insertions(+)

3. Apply and verify the changes

Add the second DNS record for www.example.com.

$ terraform apply --auto-approve
cloudflare_record.www: Refreshing state... (ID: c38d3103767284e7cd14d5dad3ab8668)
cloudflare_zone_settings_override.example-com-settings: Refreshing state... (ID: e2e6491340be87a3726f91fc4148b126)
cloudflare_rate_limit.login-limit: Refreshing state... (ID: 8d518c5d6e63406a9466d83cb8675bb6)
cloudflare_record.www-asia: Creating...
created_on: "" => "<computed>"
domain: "" => "example.com"
hostname: "" => "<computed>"
metadata.%: "" => "<computed>"
modified_on: "" => "<computed>"
name: "" => "www"
proxiable: "" => "<computed>"
proxied: "" => "true"
ttl: "" => "<computed>"
type: "" => "A"
value: "" => "198.51.100.15"
zone_id: "" => "<computed>"
cloudflare_record.www-asia: Creation complete after 1s (ID: fda39d8c9bf909132e82a36bab992864)
Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

With the second DNS record in place, make some requests to see where the traffic is served from.

$ for curl https://www.example.com
Hello, this is 203.0.113.10!
$ curl https://www.example.com
Hello, this is 203.0.113.10!
$ curl https://www.example.com
Hello, this is 198.51.100.15!
$ curl https://www.example.com
Hello, this is 203.0.113.10!

As noted above, there is no discernible pattern for which origin receives the request. When Cloudflare connects to an origin with multiple DNS records, one of the IP addresses is selected at random. If both IPs are in the same data center and sessions can be shared (i.e., it doesn't matter if the same user hops between origin servers), this may work fine. However, for anything more complicated, such as origins in different geographies or active health checks, you will want to use Cloudflare's Load Balancing product.

4. Switch to using Cloudflare's Load Balancing product

As described in the Load Balancing tutorial, you will need to complete three tasks:

  1. Create a monitor to run health checks against your origin servers.
  2. Create a pool of one or more origin servers that will receive load balanced traffic.
  3. Create a load balancer with an external hostname, e.g., www.example.com, and one or more pools.

i. Define and create the health check ("monitor")

To monitor the origins, create a basic health check that makes a GET request to each origin on the URL https://www.example.com. If the origin returns the 200/OK status code within five seconds, it is considered healthy. If it fails to do so three times in a row, it is considered unhealthy. This health check will be run once per minute from several regions and send an email notification to you@example.com if any failures are detected.

$ git checkout step5-loadbalance
Switched to branch 'step5-loadbalance'
$ cat >> cloudflare.tf <<'EOF'
resource "cloudflare_load_balancer_monitor" "get-root-https" {
expected_body = "alive"
expected_codes = "200"
method = "GET"
timeout = 5
path = "/"
interval = 60
retries = 2
check_regions = ["WNAM", "ENAM", "WEU", "EEU", "SEAS", "NEAS"]
description = "GET / over HTTPS - expect 200"
}
EOF

ii. Define and create the pool of origins

In this exammple, the pool will be called "www-servers" with two origins added to it: www-us (203.0.113.10) and www-asia (198.51.100.15). For now, skip any sort of geo routing.

Note the reference to the monitor added in the last step. When applying this confirmation, Terraform will figure out that it first needs to create the monitor before looking up the ID and providing it to the pool you wish to create.

$ cat >> cloudflare.tf <<'EOF'
resource "cloudflare_load_balancer_pool" "www-servers" {
name = "www-servers"
monitor = cloudflare_load_balancer_monitor.get-root-https.id
origins {
name = "www-us"
address = "203.0.113.10"
}
origins {
address = "198.51.100.15"
name = "www-asia"
}
description = "www origins"
enabled = true
minimum_origins = 1
notification_email = "you@example.com"
}
EOF

iii. Define and create the load balancer

When you create a load balancer (LB), it will replace any existing DNS records with the same name. For example, if you create the www.example.com LB below, it will supersede the two www DNS records that you previously defined. One benefit of leaving the DNS records in place is that if you temporarily disable load balancing, connections to this hostname are still possible as shown in step #2 above.

$ cat >> cloudflare.tf <<'EOF'
resource "cloudflare_load_balancer" "www-lb" {
zone_id = var.zone_id
name = "www-lb"
default_pool_ids = [cloudflare_load_balancer_pool.www-servers.id]
fallback_pool_id = cloudflare_load_balancer_pool.www-servers.id
description = "example load balancer"
proxied = true
}
EOF

iv. Preview and merge the changes

As usual, review proposed plan before applying any changes.

$ terraform plan
Refreshing Terraform state in-memory prior to plan...
The refreshed state will be used to calculate this plan, but will not be
persisted to local or remote state storage.
cloudflare_rate_limit.login-limit: Refreshing state... (ID: 8d518c5d6e63406a9466d83cb8675bb6)
cloudflare_record.www: Refreshing state... (ID: c38d3103767284e7cd14d5dad3ab8669)
cloudflare_record.www-asia: Refreshing state... (ID: fda39d8c9bf909132e82a36bab992864)
cloudflare_zone_settings_override.example-com-settings: Refreshing state... (ID: e2e6491340be87a3726f91fc4148b126)
------------------------------------------------------------------------
An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
+ create
Terraform will perform the following actions:
+ cloudflare_load_balancer.www-lb
id: <computed>
created_on: <computed>
default_pool_ids.#: <computed>
description: "example load balancer"
fallback_pool_id: <computed>
modified_on: <computed>
name: "www-lb"
pop_pools.#: <computed>
proxied: "true"
region_pools.#: <computed>
ttl: <computed>
zone: "example.com"
zone_id: <computed>
+ cloudflare_load_balancer_monitor.get-root-https
id: <computed>
created_on: <computed>
description: "GET / over HTTPS - expect 200"
expected_body: "alive"
expected_codes: "200"
interval: "60"
method: "GET"
modified_on: <computed>
path: "/"
retries: "2"
timeout: "5"
type: "http"
+ cloudflare_load_balancer_pool.www-servers
id: <computed>
check_regions.#: "6"
check_regions.1151265357: "SEAS"
check_regions.1997072153: "WEU"
check_regions.2367191053: "EEU"
check_regions.2826842289: "ENAM"
check_regions.2992567379: "WNAM"
check_regions.3706632574: "NEAS"
created_on: <computed>
description: "www origins"
enabled: "true"
minimum_origins: "1"
modified_on: <computed>
monitor: <computed>
name: "www-servers"
notification_email: "you@example.com"
origins.#: "2"
origins.3039426352.address: "198.51.100.15"
origins.3039426352.enabled: "true"
origins.3039426352.name: "www-asia"
origins.4241861547.address: "203.0.113.10"
origins.4241861547.enabled: "true"
origins.4241861547.name: "www-us"
Plan: 3 to add, 0 to change, 0 to destroy.
------------------------------------------------------------------------
Note: You didn't specify an "-out" parameter to save this plan, so Terraform
can't guarantee that exactly these actions will be performed if
"terraform apply" is subsequently run.

The plan looks good, so you can merge it in and apply it.

$ git add cloudflare.tf
$ git commit -m "Step 5 - Create load balancer (LB) monitor, LB pool, and LB."
[step5-loadbalance bc9aa9a] Step 5 - Create load balancer (LB) monitor, LB pool, and LB.
1 file changed, 35 insertions(+)
e$ terraform apply --auto-approve
cloudflare_zone_settings_override.example-com-settings: Refreshing state... (ID: e2e6491340be87a3726f91fc4148b126)
cloudflare_rate_limit.login-limit: Refreshing state... (ID: 8d518c5d6e63406a9466d83cb8675bb6)
cloudflare_record.www: Refreshing state... (ID: c38d3103767284e7cd14d5dad3ab8669)
cloudflare_record.www-asia: Refreshing state... (ID: fda39d8c9bf909132e82a36bab992864)
cloudflare_load_balancer_monitor.get-root-https: Creating...
created_on: "" => "<computed>"
description: "" => "GET / over HTTPS - expect 200"
expected_body: "" => "alive"
expected_codes: "" => "200"
interval: "" => "60"
method: "" => "GET"
modified_on: "" => "<computed>"
path: "" => "/"
retries: "" => "2"
timeout: "" => "5"
type: "" => "http"
cloudflare_load_balancer_monitor.get-root-https: Creation complete after 1s (ID: 4238142473fcd48e89ef1964be72e3e0)
cloudflare_load_balancer_pool.www-servers: Creating...
check_regions.#: "" => "6"
check_regions.1151265357: "" => "SEAS"
check_regions.1997072153: "" => "WEU"
check_regions.2367191053: "" => "EEU"
check_regions.2826842289: "" => "ENAM"
check_regions.2992567379: "" => "WNAM"
check_regions.3706632574: "" => "NEAS"
created_on: "" => "<computed>"
description: "" => "www origins"
enabled: "" => "true"
minimum_origins: "" => "1"
modified_on: "" => "<computed>"
monitor: "" => "4238142473fcd48e89ef1964be72e3e0"
name: "" => "www-servers"
notification_email: "" => "you@example.com"
origins.#: "" => "2"
origins.3039426352.address: "" => "198.51.100.15"
origins.3039426352.enabled: "" => "true"
origins.3039426352.name: "" => "www-asia"
origins.4241861547.address: "" => "203.0.113.10"
origins.4241861547.enabled: "" => "true"
origins.4241861547.name: "" => "www-us"
cloudflare_load_balancer_pool.www-servers: Creation complete after 0s (ID: 906d2a7521634783f4a96c062eeecc6d)
cloudflare_load_balancer.www-lb: Creating...
created_on: "" => "<computed>"
default_pool_ids.#: "" => "1"
default_pool_ids.0: "" => "906d2a7521634783f4a96c062eeecc6d"
description: "" => "example load balancer"
fallback_pool_id: "" => "906d2a7521634783f4a96c062eeecc6d"
modified_on: "" => "<computed>"
name: "" => "www-lb"
pop_pools.#: "" => "<computed>"
proxied: "" => "true"
region_pools.#: "" => "<computed>"
ttl: "" => "<computed>"
zone: "" => "example.com"
zone_id: "" => "<computed>"
cloudflare_load_balancer.www-lb: Creation complete after 1s (ID: cb94f53f150e5c1a65a07e43c5d4cac4)
Apply complete! Resources: 3 added, 0 changed, 0 destroyed.

v. Test the changes

With load balancing in place, run thee curl requests again to see where the traffic is served from.

$ for i in {1..4}; do curl https://www.example.com && sleep 5; done
Hello, this is 198.51.100.15!
Hello, this is 203.0.113.10!
Hello, this is 198.51.100.15!
Hello, this is 203.0.113.10!

You should now see each request load balanced evenly across the two origins we defined.