website: switch to prettier demo
This commit is contained in:
Michael Schurter
parent
af0e7b8495
commit
5594739eb4
|
|
@ -70,107 +70,187 @@ Alternatively if you know the network interface Nomad should use:
|
|||
$ sudo nomad agent -dev -network-interface eth0
|
||||
```
|
||||
|
||||
## Run Redis Container
|
||||
## Run the Connect-enabled Services
|
||||
|
||||
Run the following job specification using `nomad run`. This job uses the
|
||||
`network` stanza in its task group with `bridge` networking mode. This enables
|
||||
all tasks in the same group to share the same network, and other allocations,
|
||||
even on the same node, cannot. The `connect` stanza enables Consul Connect
|
||||
functionality for this container. Nomad will launch a proxy for this container
|
||||
that registers itself in Consul.
|
||||
Once Nomad and Consul are running submit the following Connect-enabled services
|
||||
to Nomad by copying the HCL into a file named `connect.nomad` and running:
|
||||
`nomad run connect.nomad`
|
||||
|
||||
```hcl
|
||||
job "redis" {
|
||||
datacenters = ["dc1"]
|
||||
job "countdash" {
|
||||
datacenters = ["dc1"]
|
||||
group "api" {
|
||||
network {
|
||||
mode = "bridge"
|
||||
}
|
||||
|
||||
group "cache" {
|
||||
network {
|
||||
mode = "bridge"
|
||||
}
|
||||
service {
|
||||
name = "count-api"
|
||||
port = "9001"
|
||||
|
||||
service {
|
||||
name = "redis-cache"
|
||||
tags = ["global", "cache"]
|
||||
connect {
|
||||
sidecar_service {}
|
||||
}
|
||||
}
|
||||
|
||||
# This is the port within the network namespace that the task listens on.
|
||||
# The Envoy proxy itself listens on a random port.
|
||||
port = "6379"
|
||||
task "web" {
|
||||
driver = "docker"
|
||||
config {
|
||||
image = "hashicorpnomad/counter-api:v1"
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
connect {
|
||||
sidecar_service { }
|
||||
}
|
||||
}
|
||||
group "dashboard" {
|
||||
network {
|
||||
mode ="bridge"
|
||||
port "http" {
|
||||
static = 9002
|
||||
to = 9002
|
||||
}
|
||||
}
|
||||
|
||||
task "redis" {
|
||||
driver = "docker"
|
||||
service {
|
||||
name = "count-dashboard"
|
||||
port = "9002"
|
||||
|
||||
config {
|
||||
image = "redis:3.2"
|
||||
}
|
||||
connect {
|
||||
sidecar_service {
|
||||
proxy {
|
||||
upstreams {
|
||||
destination_name = "count-api"
|
||||
local_bind_port = 8080
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
resources {
|
||||
cpu = 500
|
||||
memory = 256
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
task "dashboard" {
|
||||
driver = "docker"
|
||||
env {
|
||||
COUNTING_SERVICE_URL = "http://${NOMAD_UPSTREAM_ADDR_count_api}"
|
||||
}
|
||||
config {
|
||||
image = "hashicorpnomad/counter-dashboard:v1"
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
## Run the web application
|
||||
#### TODO change the example container
|
||||
The job contains two task groups: an API service and a web frontend.
|
||||
|
||||
Run the following job specification using `nomad run`. This container is a web application
|
||||
that uses Redis. It declares Redis as its upstream service through the `sidecar_service` stanza.
|
||||
It also specifies a local bind port. This is the port on which the proxy providing secure communication
|
||||
to Redis listens on.
|
||||
### API Service
|
||||
|
||||
The API service is defined as a task group with a bridge network:
|
||||
|
||||
```hcl
|
||||
job "api" {
|
||||
datacenters = ["dc1"]
|
||||
group "api" {
|
||||
network {
|
||||
mode = "bridge"
|
||||
}
|
||||
|
||||
group "api" {
|
||||
network {
|
||||
mode = "bridge"
|
||||
|
||||
port "http" {
|
||||
to = 8080
|
||||
static = 8080
|
||||
}
|
||||
}
|
||||
|
||||
service {
|
||||
name = "api"
|
||||
port = "http"
|
||||
|
||||
connect {
|
||||
sidecar_service {
|
||||
proxy {
|
||||
upstreams {
|
||||
destination_name = "redis-cache"
|
||||
local_bind_port = 6379
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
task "api" {
|
||||
driver = "docker"
|
||||
|
||||
config {
|
||||
image = "schmichael/rediweb:0.2"
|
||||
}
|
||||
|
||||
resources {
|
||||
cpu = 200
|
||||
memory = 100
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
...
|
||||
}
|
||||
```
|
||||
|
||||
After running this job, visit the Nomad UI to see the Envoy proxies managed by Nomad
|
||||
both for the web application and its upstream Redis service. The Consul UI also shows
|
||||
the registered Connect proxies.
|
||||
Since the API service is only accessible via Consul Connect, it does not define
|
||||
any ports in its network. The service stanza enables Connect:
|
||||
|
||||
```hcl
|
||||
group "api" {
|
||||
...
|
||||
|
||||
service {
|
||||
name = "count-api"
|
||||
port = "9001"
|
||||
|
||||
connect {
|
||||
sidecar_service {}
|
||||
}
|
||||
}
|
||||
|
||||
...
|
||||
}
|
||||
```
|
||||
|
||||
The `port` in the service stanza is the port the API service listens on. The
|
||||
Envoy proxy will automatically route traffic to that port inside the network
|
||||
namespace.
|
||||
|
||||
### Web Frontend
|
||||
|
||||
The web frontend is defined as a task group with a bridge network and a static
|
||||
forwarded port:
|
||||
|
||||
```hcl
|
||||
group "dashboard" {
|
||||
network {
|
||||
mode ="bridge"
|
||||
port "http" {
|
||||
static = 9002
|
||||
to = 9002
|
||||
}
|
||||
}
|
||||
|
||||
...
|
||||
}
|
||||
```
|
||||
|
||||
The `static = 9002` parameter requests the Nomad scheduler reserve port 9002 on
|
||||
a host network interface. The `to = 9002` parameter forwards that host port to
|
||||
port 9002 inside the network namespace.
|
||||
|
||||
This allows you to connect to the web frontend in a browser by visiting
|
||||
`http://<host_ip>:9002`.
|
||||
|
||||
The web frontend connects to the API service via Consul Connect:
|
||||
|
||||
```hcl
|
||||
service {
|
||||
name = "count-dashboard"
|
||||
port = "9002"
|
||||
|
||||
connect {
|
||||
sidecar_service {
|
||||
proxy {
|
||||
upstreams {
|
||||
destination_name = "count-api"
|
||||
local_bind_port = 8080
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
The `upstreams` stanza defines the remote service to access (`count-api`) and
|
||||
what port to expose that service on inside the network namespace (`8080`).
|
||||
|
||||
The web frontend is configured to communicate with the API service with an
|
||||
environment variable:
|
||||
|
||||
```hcl
|
||||
env {
|
||||
COUNTING_SERVICE_URL = "http://${NOMAD_UPSTREAM_ADDR_count_api}"
|
||||
}
|
||||
```
|
||||
|
||||
The web frontend is configured via the `$COUNTING_SERVICE_URL`, so you must
|
||||
interpolate the upstream's address into that environment variable. Note that
|
||||
dashes (`-`) are converted to underscores (`_`) in environment variables so
|
||||
`count-api` becomes `count_api`.
|
||||
|
||||
## Limitations
|
||||
|
||||
Prior to Nomad 0.10.0's final release, the Consul Connect integration has
|
||||
several limitations that have yet to be addressed:
|
||||
|
||||
- Jobs with a `connect` stanza may not update properly. Workaround this by
|
||||
stopping and starting Connect-enabled jobs.
|
||||
- Only the Docker, exec, and raw exec drivers support network namespaces and
|
||||
Connect.
|
||||
- Not all Connect configuration options in Consul are available in Nomad.
|
||||
- The Envoy proxy is not yet configurable and is hardcoded to use 100 MHz of
|
||||
cpu and 300 MB of memory.
|
||||
|
|
|
|||
Loading…
Reference in New Issue