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137 строки
7.3 KiB
Markdown
137 строки
7.3 KiB
Markdown
# HTTP Routing Mesh (HRM)
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> **NOTE:** This lab assumes two things.
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>1. You have configured DNS name resolution for red.example.com and white.example.com to point to a load balancer. This name resolution is required for your laptop/desktop and not the Docker nodes that will make up your UCP cluster. Therefore, it can be as simple as a couple of entries in the local `hosts` file of your laptop or desktop. As long as your web browser can resolve red.example.com and white.example.com to a load balancer in front of your Swarm this lab will work.
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>2. You have configured an external load balancer to accept connections for the two DNS names above and to load balance across all nodes in a UCP cluster.
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# Lab Meta
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> **Difficulty**: Intermediate
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> **Time**: Approximately 15 minutes
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In this lab you'll learn how to configure and use the *HTTP Routing Mesh* with *Docker Datacenter*.
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You will complete the following steps as part of this lab.
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- [Step 1 - Enable the HTTP Routing Mesh (HRM)](#enable_hrm)
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- [Step 2 - Verify the HRM](#verify_hrm)
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- [Step 3 - Create the RED service](#create_red)
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- [Step 4 - Create the WHITE service](#create_white)
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- [Step 5 - Test the configuration](#test)
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# Prerequisites
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You will need all of the following to complete this lab:
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- A UCP Cluster running **Docker 1.12** or higher
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- Credentials to log in to UCP, create services, and enable the HRM
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- Name resolution configured for two DNS names (your lab instructor will give you these)
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Your instructor will provide you with the details you require.
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> **NOTE:** Throughout this guide we will use *red.example.com* and *white.example.com*. As per the note above, you will need to configure this yourself. You can also substitute other names if you like.That would mean that any time you see *red.example.com* and *white.example.com* you will need to substitute these for *red.* and *white.<your-domain-goes-here>*.
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# <a name="enable_hrm"></a>Step 1: Enable the HTTP Routing Mesh (HRM)
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1. Use a web browser to connect to the Login page of your UCP cluster
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2. Enter your credentials as supplied by your lab instructor
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3. Navigate to `Admin Settings` > `Routing Mesh` and enable the HTTP Routing Mesh (HRM) on port 80.
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The HRM is now configured and ready to use.
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# <a name="verify_hrm"></a>Step 2: Verify the HRM
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Enabling the HRM creates a new *service* called `ucp-hrm` and a new network called `ucp-hrm`. In this step we'll confirm that both of these constructs have been created correctly.
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Execute the following steps in the UCP web UI.
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1. Navigate to `Resources` > `Networks` and check for the presence of the `ucp-hrm` network. You may have to `search` for it.
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The network shows as an overlay network scoped to the entire Swarm cluster.
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2. Navigate to `Resources` > `Services` and click the checkbox to `Show system services`.
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The image above shows the `ucp-hrm` service up and running.
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You have now verified that the HRM was configured successfully.
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In the next two steps you'll create two services. Each service will based off the same `ehazlett/docker-demo:latest` image, and runs a web server that counts containers and requests. You will configure each service with a different number of tasks and each with a different value in the `TITLE` variable.
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# <a name="create_red"></a>Step 3: Create the RED service
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In this step you'll create a new service called **RED**, and configure it to use the HRM.
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1. In `DDC` click `Resources` > `Services` and then `+Create Service`.
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2. Configure the service as follows (leave all other options as default and remember to substitute "red.example.com" with the DNS name from your environment):
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- Name: `RED`
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- Image: `ehazlett/docker-demo:latest`
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- Scale: `10`
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- Arguments: `-close-conn`
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- Published port: Port = `8080/tcp`, Public Port = `5000`
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- Attached Networks: `ucp-hrm`
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- Labels: `com.docker.ucp.mesh.http` = `8080=http://red.example.com`
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- Environment Variables: `TITLE` = `RED`
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It will take a few minutes for this service to pull down the image and start. Continue with the next step to create the **WHITE** service.
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# <a name="create_white"></a>Step 4: Create the WHITE service
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In this step you'll create a new service called **WHITE**. The service will be very similar to the **RED** service created in the previous step.
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1. In `DDC` click `Resources` > `Services` and then `+Create Service`.
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2. Configure the service as follows (leave all other options as default and remember to substitute "red.example.com" with the DNS name from your environment):
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- Name: `RWHITE`
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- Image: `ehazlett/docker-demo:latest`
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- Scale: `5`
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- Arguments: `-close-conn`
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- Published port: Port = `8080/tcp`, Public Port = `5001`
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- Attached Networks: `ucp-hrm`
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- Labels: `com.docker.ucp.mesh.http` = `8080=http://white.example.com`
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- Environment Variables: `TITLE` = `WHITE`
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This service will start instantaneously as the image is already pulled on every host in your UCP cluster.
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3. Verify that both services are up and running by clicking `Resources` > `Services` and checking that both services are running as shown below.
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You now have two services running. Both are connected to the `ucp-hrm` network and both have the `com.docker.ucp.mesh.http` label. The **RED** service is associated with HTTP requests for `red.example.com` and the **WHITE** service is associated with HTTP requests for `white.example.com`. This mapping of labels to URLs is leveraged by the `ucp-hrm` service which is published on port 80.
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# <a name="test"></a>Step 5: Test the configuration
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> **NOTE: DNS name resolution is required for this step. This can obviously be via the local hosts file, but this step will not work unless the URLs specified in the `com.docker.ucp.mesh.http` labels resolve to the UCP cluster nodes (probably via a load balancer).**
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In this step you will use your web browser to issue HTTP requests to `red.example.com` and `white.example.com`. DNS name resolution is configured so that these URLs resolve to a load balancer which in turn balances requests across all nodes in the UCP cluster.
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> Remember to substitute `example.com` with the domain supplied by your lab instructor.
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1. Open a web browser tab and point it to `red.example.com`.
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The text below the whale saying "RED" indicates that this request was answered by the **RED** service. This is because the `TITLE` environment variable for the **RED** service was configured to display "RED" here. You also know it is the **RED** service as this was the service configured with 10 replicas (containers).
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2. Open another tab to `white.example.com`.
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The output above shows that this request was routed to the **WHITE** service as it displays "WHITE" below the whale and only has 5 replicas (containers).
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Congratulations. You configured two services in the same Swarm (UCP cluster) to respond to requests on port 80. Traffic to each service is routed based on the URL included in the `host` field of the HTTP header.
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Requests arrive to the Swarm on port 80 and are forwarded to the `ucp-hrm` system service. The `ucp-hrm` service inspects the HTTP headers of requests and routes them to the service with the matching `com.docker.ucp.mesh.http` label.
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