The story is real, but what is the part of TCP Routing you need to know about still?
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Photo by Gary Bendig on Unsplash
The documentation to configure Cloud Foundry for TCP Routing is a great reference for getting started on your journey to implementation but there a few missing pieces which I think I can help fill in if you are deploying on AWS.
Assumptions
- I need an ELB to listen on tcp ports 40000-50000 and forward the traffic to the tcp-routers. The default range of 1024-1033 is fine for some folks, others, not so much.
- I want to use a
vm_extension
to addtcp-router
‘s as they are recreated without manual intervention. - I have an AWS account with an ELB listeners quota of 100 and I want to use all 100 ips
- I want to use Terraform to create the ELB and any necessary supporting resources.
A quick side bar: why an ELB instead of a NLB?
I’m glad you asked. My goal is to have as many tcp ports as possible with a single load balancer. As of this writing, NLB’s have a default quota of 50 target groups, each target group can manage a single port. A classic ELB has a default quota of 100 listeners. 100 > 50, therefore the ELB wins!
The link to the soft quota limit for ELB listeners is at https://docs.aws.amazon.com/servicequotas/latest/userguide/request-quota-increase.html
Steps to Implement
- Create the ELB with Terraform
- Use the ELB name to modify the Cloud Config
- Create the ops file
- Set router groups with
cf curl
- Use
cf
cli to create shared domain - Test with an app
Step 1: Create the ELB with Terraform
This is one of the places where the documentation isn’t 100% helpful, however the good people who have been maintaining BBL help us out. In particular this chunk of Terraform is a great place to start: https://github.com/cloudfoundry/bosh-bootloader/blob/main/terraform/aws/templates/cf_lb.tf#L244-L1041
To support a different range of ips requires a few easy changes. Start by replacing the ingress
block in the two security group definitions:
ingress {
security_groups = ["${aws_security_group.cf_tcp_lb_security_group.id}"]
protocol = "tcp"
from_port = 1024
to_port = 1123
}
with
ingress {
security_groups = ["${aws_security_group.cf_tcp_lb_security_group.id}"]
protocol = "tcp"
from_port = 40000
to_port = 40099
}
You’ll also need to replace the block of listeners
defined in the resource aws_elb.cf_tcp_lb
:
listener {
instance_port = 1024
instance_protocol = "tcp"
lb_port = 1024
lb_protocol = "tcp"
}
...
98 bottles of listeners on the wall, 98 bottles of listeners...
...
listener {
instance_port = 1123
instance_protocol = "tcp"
lb_port = 1123
lb_protocol = "tcp"
}
With something like:
listener {
instance_port = 40000
instance_protocol = "tcp"
lb_port = 40000
lb_protocol = "tcp"
}
...
98 bottles of listeners on the wall, 98 bottles of listeners...
...
listener {
instance_port = 40099
instance_protocol = "tcp"
lb_port = 40099
lb_protocol = "tcp"
}
Don’t feel like copy/paste/modifying the same 6 lines of code 99 times? Here’s a quick python
script that you can run, then copy/paste the results into the Terraform file:
start_port = int(input("Enter starting port (40000):") or "40000")
end_port = int(input("Enter ending port (40099):") or 40099) + 1
for x in range(start_port, end_port):
print(" listener {")
print(' instance_port =', x)
print(' instance_protocol = "tcp"')
print(" lb_port =", x)
print(' lb_protocol = "tcp"')
print(" }")
Cute, right? Anyway, I called this listeners.py
which I can run with python3 listeners.py
, copy in the output and enjoy.
If you are going to just use the section of BBL code highlighted with the few changes above you’ll need to provide a couple more values for your terraform:
subnets
– No guidance here other than to pick two subnets in your VPCvar.env_id
– When in doubt,variable "env_id" { default = "starkandwayne"}
short_env_id
– When in doubt,variable "short_env_id" { default = "sw"}
. Shameless plug, I know.
After your terraform run is complete, you’ll see output like:
Outputs:
cf_tcp_lb_internal_security_group = sg-0f9b6a5c6d63f1375
cf_tcp_lb_name = sw-cf-tcp-lb
cf_tcp_lb_security_group = sg-0e5cd4f4f262a8d87
cf_tcp_lb_url = sw-cf-tcp-lb-1943122948.us-west-2.elb.amazonaws.com
Register the ELB CNAME with your DNS provider to point to tcp.APP_DOMAIN
, in my case:
- My apps are in
*.apps.codex.starkandwayne.com
- Therefore I’m using
tcp.apps.codex.starkandwayne.com
as my TCP url I need to register with DNS - So
tcp.apps.codex.starkandwayne.com
has a CNAME record added forsw-cf-tcp-lb-1943122948.us-west-2.elb.amazonaws.com
Step 2 – Configure Cloud Config
Add to cloud config:
vm_extensions:
- name: cf-tcp-router-network-properties
cloud_properties:
elbs:
- sw-cf-tcp-lb # Your name will be in the terraform output as `cf_tcp_lb_name`
A quick update to the bosh director:
$ bosh -e dev update-config --type cloud --name dev dev.yml
Using environment 'https://10.4.16.4:25555' as user 'admin'
vm_extensions:
- name: cf-tcp-router-network-properties
+ cloud_properties:
+ elbs:
+ - sw-cf-tcp-lb
Continue? [yN]:
If you take a peek at cf-deployment
you’ll see that the tcp-router
is looking for a vm_extension
called cf-tcp-router-network-properties
here: https://github.com/cloudfoundry/cf-deployment/blob/v20.2.0/cf-deployment.yml#L1433-L1434 so once you configure the cloud config, cf-deployment
is already configured to use the extension. What this means is whenever a tcp-router
instance is created, BOSH will automatically add it back to the ELB once it passes the health check.
Step 3 – Create the ops file
Since I need a custom port range, some of the properties in cf-deployment.yml
need to be changed.
An example ops file to change ports for the routing release:
- path: /instance_groups/name=api/jobs/name=routing-api/properties/routing_api/router_groups/name=default-tcp?
type: replace
value:
name: default-tcp
reservable_ports: 40000-40099
type: tcp
When you include this new ops file in your deployment you’ll see the change with:
Task 4856 done
instance_groups:
- name: api
jobs:
- name: routing-api
properties:
routing_api:
router_groups:
- name: default-tcp
- reservable_ports: 1024-1033
+ reservable_ports: 40000-40099
Step 4 – Set router groups via cf curl
Post deployment however CAPI still has the old ports:
$ cf curl /routing/v1/router_groups
[
{
"guid": "abe622af-2246-43a2-73f8-79bcb8e0cbb4",
"name": "default-tcp",
"type": "tcp",
"reservable_ports": "1024-1033"
}
]
To configure the Cloud Controller with the range of ips to use:
$ cf curl -X PUT -d '{"reservable_ports":"40000-40099"}' /routing/v1/router_groups/abe622af-2246-43a2-73f8-79bcb8e0cbb4
Step 5 – Create shared domain
The DNS is configured for tcp.apps.codex.starkandwayne.com
and the name of the router group from the ops file is default-tcp
. Using the cf
cli Cloud Foundry can then be configured to map these two togther into a shared domain:
cf create-shared-domain tcp.apps.codex.starkandwayne.com --router-group default-tcp
If you run the cf domains
command you’ll see the new tcp domain added with type = tcp
$ cf domains
Getting domains in org system as admin...
name status type details
apps.codex.starkandwayne.com shared
tcp.apps.codex.starkandwayne.com shared tcp
system.codex.starkandwayne.com owned
Step 6 – Push an App
To create an app using tcp, there are a few options:
- With the
cf
cli v6: Push the app with the domain specified and a random portcf push myapp -d tcp.apps.codex.starkandwayne.com --random-route
- Create a route for a space, push an app, then map the route to the space.
$ cf create-route tcp.apps.codex.starkandwayne.com --port 40001 $ cf push myapp --no-route # see next section for example app $ cf map-route myapp tcp.apps.codex.starkandwayne.com --port 40001
- Create an app manifest which contains
routes:
, then specify the app manifest in the cf push (cf push -f manifest.yml
) with the contents ofmanifest.yml
being:applications: - name: cf-env memory: 256M routes: - route: tcp.apps.codex.starkandwayne.com
In the previous examples, swap --port
with --random-route
for the app push to pick any available port instead of a bespoke one. This will help developers from having to guess which ports are still available.
Testing an App
Once the application is pushed, for instance with cf push myapp -d tcp.apps.codex.starkandwayne.com --random-route
which uses cf-env
, you can use curl
to test the access:
$ curl http://tcp.apps.codex.starkandwayne.com:40001
<html><body style="margin:0px auto; width:80%; font-family:monospace"><head><title>Cloud Foundry Environment</title><meta name="viewport" content="width=device-width"></head><h2>Cloud Foundry Environment</h2><div><table><tr><td><strong>BUNDLER_ORIG_BUNDLER_VERSION</strong></td><td>BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL</tr><tr><td><strong>BUNDLER_ORIG_BUNDLE_BIN_PATH</strong></td><td>BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL</tr><tr><td><strong>BUNDLER_ORIG_BUNDLE_GEMFILE</strong></td><td>/home/vcap/app/Gemfile</tr><tr><td><strong>BUNDLER_ORIG_GEM_HOME</strong></td><td>/home/vcap/deps/0/gem_home</tr><tr><td><strong>BUNDLER_ORIG_GEM_PATH</strong></td><td>/home/vcap/deps/0/vendor_bundle/ruby/2.7.0:/home/vcap/deps/0/gem_home:/home/vcap/deps/0/bundler</tr><tr><td><strong>BUNDLER_ORIG_MANPATH</strong></td><td>BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL</tr><tr><td><strong>BUNDLER_ORIG_PATH</strong></td><td>/home/vcap/deps/0/bin:/usr/local/bin:/usr/bin:/bin</tr><tr><td><strong>BUNDLER_ORIG_RB_USER_INSTALL</strong></td><td>BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL</tr><tr><td><strong>BUNDLER_ORIG_RUBYLIB</strong></td><td>BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL</tr><tr><td><strong>BUNDLER_ORIG_RUBYOPT</strong></td><td>BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL</tr><tr><td><strong>BUNDLER_VERSION</strong></td><td>2.2.28</tr><tr><td><strong>BUNDLE_BIN</strong></td><td>/home/vcap/deps/0/binstubs</tr><tr><td><strong>BUNDLE_BIN_PATH</strong></td><td>/home/vcap/deps/0/bundler/gems/bundler-2.2.28/exe/bundle</tr><tr><td><strong>BUNDLE_GEMFILE</strong></td><td>/home/vcap/app/Gemfile</tr><tr><td><strong>BUNDLE_PATH</strong></td><td>/home/vcap/deps/0/vendor_bundle</tr><tr><td><strong>CF_INSTANCE_ADDR</strong></td><td>10.4.23.17:61020</tr><tr><td><strong>CF_INSTANCE_CERT</strong></td><td>/etc/cf-instance-credentials/instance.crt</tr><tr><td><strong>CF_INSTANCE_GUID</strong></td><td>32064364-6709-44b9-4a91-a1f3</tr><tr><td><strong>CF_INSTANCE_INDEX</strong></td><td><pre>0</pre></tr><tr><td><strong>CF_INSTANCE_INTERNAL_IP</strong></td><td>10.255.103.15</tr><tr><td><strong>CF_INSTANCE_IP</strong></td><td>10.4.23.17</tr><tr><td><strong>CF_INSTANCE_KEY</strong></td><td>/etc/cf-instance-credentials/instance.key</tr><tr><td><strong>CF_INSTANCE_PORT</strong></td><td><pre>61020</pre></tr><tr><td><strong>CF_INSTANCE_PORTS</strong></td><td><pre>[
{
"external": 61020,
"internal": 8080,
"external_tls_proxy": 61022,
"internal_tls_proxy": 61001
},
{
"external": 61021,
"internal": 2222,
"external_tls_proxy": 61023,
"internal_tls_proxy": 61002
}
]</pre></tr><tr><td><strong>CF_SYSTEM_CERT_PATH</strong></td><td>/etc/cf-system-certificates</tr><tr><td><strong>DEPS_DIR</strong></td><td>/home/vcap/deps</tr><tr><td><strong>GEM_HOME</strong></td><td>/home/vcap/deps/0/vendor_bundle/ruby/2.7.0</tr><tr><td><strong>GEM_PATH</strong></td><td></tr><tr><td><strong>HOME</strong></td><td>/home/vcap/app</tr><tr><td><strong>INSTANCE_GUID</strong></td><td>32064364-6709-44b9-4a91-a1f3</tr><tr><td><strong>INSTANCE_INDEX</strong></td><td><pre>0</pre></tr><tr><td><strong>LANG</strong></td><td>en_US.UTF-8</tr><tr><td><strong>MEMORY_LIMIT</strong></td><td>256m</tr><tr><td><strong>OLDPWD</strong></td><td>/home/vcap</tr><tr><td><strong>PATH</strong></td><td>/home/vcap/deps/0/vendor_bundle/ruby/2.7.0/bin:/home/vcap/deps/0/bin:/usr/local/bin:/usr/bin:/bin</tr><tr><td><strong>PORT</strong></td><td><pre>8080</pre></tr><tr><td><strong>PWD</strong></td><td>/home/vcap/app</tr><tr><td><strong>RACK_ENV</strong></td><td>production</tr><tr><td><strong>RAILS_ENV</strong></td><td>production</tr><tr><td><strong>RAILS_LOG_TO_STDOUT</strong></td><td>enabled</tr><tr><td><strong>RAILS_SERVE_STATIC_FILES</strong></td><td>enabled</tr><tr><td><strong>RUBYLIB</strong></td><td>/home/vcap/deps/0/bundler/gems/bundler-2.2.28/lib</tr><tr><td><strong>RUBYOPT</strong></td><td>-r/home/vcap/deps/0/bundler/gems/bundler-2.2.28/lib/bundler/setup</tr><tr><td><strong>SHLVL</strong></td><td><pre>1</pre></tr><tr><td><strong>TMPDIR</strong></td><td>/home/vcap/tmp</tr><tr><td><strong>USER</strong></td><td>vcap</tr><tr><td><strong>VCAP_APPLICATION</strong></td><td><pre>{
"application_id": "2d19faba-0cae-4cb7-8078-67c092cfcc33",
"application_name": "test",
"application_uris": [
"tcp.apps.codex.starkandwayne.com:40001"
],
"application_version": "16d2c062-932b-4902-b874-0ea519e01dd8",
"cf_api": "https://api.system.codex.starkandwayne.com",
"host": "0.0.0.0",
"instance_id": "32064364-6709-44b9-4a91-a1f3",
"instance_index": 0,
"limits": {
"disk": 1024,
"fds": 16384,
"mem": 256
},
"name": "test",
"organization_id": "d396b0c6-872f-46a2-a752-bdea51819c06",
"organization_name": "system",
"port": 8080,
"process_id": "2d19faba-0cae-4cb7-8078-67c092cfcc33",
"process_type": "web",
"space_id": "4e081328-2ac1-4509-8f51-ffcbfc012165",
"space_name": "ops",
"uris": [
"tcp.apps.codex.starkandwayne.com:40001"
],
"version": "16d2c062-932b-4902-b874-0ea519e01dd8"
}</pre></tr><tr><td><strong>VCAP_APP_HOST</strong></td><td>0.0.0.0</tr><tr><td><strong>VCAP_APP_PORT</strong></td><td><pre>8080</pre></tr><tr><td><strong>VCAP_SERVICES</strong></td><td><pre>{
}</pre></tr><tr><td><strong>_</strong></td><td>/home/vcap/deps/0/bin/bundle</tr></table></div><h2>HTTP Request Headers</h2><div><table><tr><td><strong>accept</strong></td><td>*/*</tr><tr><td><strong>host</strong></td><td>tcp.apps.codex.starkandwayne.com:40001</tr><tr><td><strong>user_agent</strong></td><td>curl/7.79.1</tr><tr><td><strong>version</strong></td><td>HTTP/1.1</tr></table></div></body></html>%
Additional Reading
These links are to documentation used to put this guide together
- Primary document on how to configure deploy CF with TCP Routing here
- Configuring routes/ports for apps after tcp routing is setup here
- bbl terraform to create the tcp load balancer here
- Trouble shoot tcp app issues here
Good Day!
PS: I grew up listening to Paul Harvey on the radio in my parent’s station wagon. You are missed good sir!