Creating an application load balancer

You can create an IBM Cloud® Application Load Balancer for VPC (ALB) to distribute inbound traffic across multiple instances. IBM supports virtual server instances, bare metal server instances, and other devices that are reachable to the application load balancer with a device IP address, such as Power Systems™ Virtual Server instances connected over IBM Cloud Direct Link.

Creating an application load balancer in the UI

To create an ALB:

From your browser, open the IBM Cloud console and log in to your account.
Select the Navigation Menu , then click VPC Infrastructure > Load balancers.
On the Load balancers page, click Create +.
For Load balancer type, select the Applicatoin Load Balancer (ALB) tile.
In the Location section, edit the following fields, if necessary.
- Geography: Indicates the geography where you want the load balancer created.
- Region: Indicates the region where you want the load balancer created.
In the Details section, complete the following information:
- Name: Enter a name for the load balancer, such as my-load-balancer.
- Resource group: Select a resource group for the load balancer.
- Tags: (Optional) Add tags to help you organize and find your resources. You can add more tags later. For more information, see Working with tags.
- Access management tags: (Optional) Add access management tags to resources to help organize access control relationships. The only supported format for access management tags is key:value. For more information, see Controlling access to resources by using tags.
- Select the Application Load Balancer (ALB) tile.
- Virtual private cloud: Select your VPC.
- Type: Select the load balancer type.
  - A public load balancer has a public IP address, which means that it can route requests from clients over the internet.
  - A private load balancer has a private IP address, which means that it is accessible only to internal clients on your private subnets, within the same region and VPC.
- For the DNS type, select either Public or Private. Private DNS zones are resolvable only on IBM Cloud, and only from explicitly permitted networks in an account or with cross-account access.
  
  For Private type only, click Bind+ to enter your DNS instance and zone information, then click Bind.
- Subnets: Select the subnets in which to create your load balancer. To maximize the availability of your application, select subnets in different zones.
  
  You cannot assign more than 15 subnets per ALB.
In the Back-end pools section, click Create pool and specify the following information to create a back-end pool. You can create one or more pools.
- Name: Enter a name for the pool, such as my-pool.
- Protocol: Select the protocol for your instances in this pool. The protocol of the pool must match the protocol of its associated listener. For example, if an HTTPS or HTTP protocol is selected for the listener, the protocol of the pool must be HTTP. Similarly, if the listener protocol is TCP, the protocol of the pool must be TCP.
- Session stickiness: Select whether all requests during a user's session are sent to the same instance.
- Method: Select how you want the load balancer to distribute traffic across the instances in the pool:
  - Round robin: Forward requests to each instance in turn. All instances receive approximately an equal number of client connections.
  - Weighted round robin: Forward requests to each instance in proportion to its assigned weight. For example, you have instances A, B, and C, and their weights are set to 60, 60 and 30. Instances A and B receive an equal number of connections, and instance C receives half as many connections.
  - Least connections: Forward requests to the instance with the least number of connections at the current time.
- Health check: Configure how the load balancer checks the health of the instances.
  - Health check path: The health check path is applicable only if HTTP is selected as the health check protocol. The health check path specifies the URL used by the load balancer to send the HTTP health check requests to the instances in the pool. By default, health checks are sent to the root path (/).
  - Health protocol: The protocol used by the load balancer to send health check messages to the instances in the pool.
  - Health port: The port on which to send health check requests. By default, health checks are sent on the same port on which traffic is sent to the instance.
  - Interval: Interval in seconds between two consecutive health check attempts. By default, health checks are sent every 5 seconds.
  - Timeout (sec): Maximum amount of time the system waits for a response from a health check request. By default, the load balancer waits 2 seconds for a response.
  - Max retries: Maximum number of health check attempts that the load balancer makes before an instance is declared unhealthy. By default, an instance is no longer considered healthy after two failed health checks.
  Although the load balancer stops sending connections to unhealthy instances, the load balancer continues monitoring the health of these instances and resumes their use if they're found healthy again (that is, if they successfully pass two consecutive health check attempts).
  
  If instances in the pool are unhealthy and you believe that your application is running fine, double check the health protocol and health path values. Also, check any security groups that are attached to the instances to ensure that the rules allow traffic between the load balancer and the instances.
Click Create to create the back-end pool.

You can attach server instances after you create your back-end pool.
To add a server instance to the new pool, click Attach server in the Server instances column of the table.
- To add VPC devices to your pool, such as virtual server instances and Bare Metal servers, select the VPC devices tab. Specify the following information for each instance:
  - Select one or more subnets from which to select an instance.
  - Select an instance. If an instance has multiple interfaces, make sure that you select the correct IP address.
  - Specify the port on which traffic is sent to the instance.
  - If your pool uses the Weighted round robin method, assign a weight for each instance.
    
    Assigning 0 weight to an instance means that no new connections are forwarded to that instance, but any existing traffic continues to flow while the current connection is active. Using a weight of 0 can help bring down an instance gracefully and remove it from service rotation.
  - Click Configure port and weight, then specify the port on which traffic is sent to the instance.
- To attach other server instances to your back-end pool, such as servers contained within an IBM Power Systems Virtual Server, select the Other tab, then click Add more. Specify the following information for each instance:
  - Specify a private IP address for the device.
  - Specify the port on which traffic is sent to the instance.
  - If your pool uses the Weighted round robin method, assign a weight for each instance.
    
    Assigning 0 weight to an instance means that no new connections are forwarded to that instance, but any existing traffic continues to flow while the current connection is active. Using a weight of 0 can help bring down an instance gracefully and remove it from service rotation.
- Click Attach to attach the server instance to your back-end pool.
In the Front-end listeners section, click Create listener and specify the following information to create a listener. You can create one or more listeners.
- Protocol: The protocol to use for receiving incoming requests.
- Proxy protocol: Select whether to allow the front-end listener to accept proxy protocol traffic.
- Port: The listening port on which requests are received.
- Back-end pool: The default back-end pool to which this listener forwards traffic.
- Max connections (optional): Maximum number of concurrent connections the listener allows.
- IAM Authorization: If HTTPS is the selected protocol for this listener, you must designate your IAM authorization, either by instance or your CRN.
- Secrets Manager: If HTTPS is the selected protocol for this listener, you must select or create a secrets manager.
- SSL certificate: If HTTPS is the selected protocol for this listener, you must select an SSL certificate. Make sure that the load balancer is authorized to access the SSL certificate.
- Timeout (sec) (optional): The maximum timeout after which the load balancer closes the connection if no data has been sent or received by the time that the idle timeout period elapses. The minimum and maximum timeout value is 50 seconds and 2 hours respectively.
Click Create to create the front-end listener.
In the Security groups section, select the security groups that you want to attach to your load balancer, or click Create to create a new security group to attach to your ALB.

Ensure that the security group allows for load-balancing traffic (listener, back-end, and health check ports). If you do not specify a security group, the default security group from your VPC attaches instead.
After you finish creating pools and listeners, click Create load balancer.
To view details of an existing load balancer, click the name of your load balancer on the Load balancers page.
If you want to redirect the traffic from an HTTP listener to an HTTPS listener, you can create an HTTP listener with HTTPS redirect settings.

Layer 7 load-balancing policies overwrite settings that you define here.

To do so:
- There must be an existing HTTPS listener before you create a new HTTP listener with HTTPS redirect.
- After the status of the load balancer changes to Active, click the Front-end listeners tab.
- In the listener list page, click Create, then specify the following information:
  - Protocol: Select your HTTP protocol.
  - Port: Choose the listening port on which requests are received.
  - Max connections (optional): Define the maximum number of concurrent connections that the listener allows.
  - HTTPS redirect: Click the toggle button to enable the HTTPS redirect configuration, then specify the following HTTPS redirect settings:
    - HTTPS listener: The target HTTPS listener, which the current HTTP listener incoming traffic is redirected to. Note that you will only see a list of HTTPS listeners whose accept_proxy_proxy value is the same as the HTTP listener.
    - Redirect URI (optional): The URL to which the request redirects.
    - Status code: The status code of the response returned by the load balancer.
If you want to redirect, forward, or reject particular incoming traffic for an HTTP or HTTPS front-end listener based on certain criteria, configure layer 7 policies.
- After the status of the load balancer changes to Active, click Front-end listeners in the navigation and click the value in the Policies column for the listener you created.
- On the Policies page, click Add policy and specify the following information to create a policy. You can create multiple policies.
  - Name: Enter a name for the policy, such as my-policy. The name must be unique within the listener.
  - Action: The action to take when all the rules for the policy match. You can reject a request with a 403 response, redirect the request to a configured URL and response code, redirect the traffic from an HTTP listener to an HTTPS listener, or forward the request to a specific back-end pool. If an incoming request does not match the rules for any policies, the request is forwarded to the default back-end pool of the listener.
  - Priority: Within each action type, policies are evaluated in ascending order of priority. Policies to reject traffic are always evaluated first, regardless of their priority. Policies to redirect traffic are evaluated next, followed by policies to forward traffic.
  - Redirect: The URL to which the request is redirected, if the action is set to Redirect.
  - Status Code: The status code of the response returned by the load balancer, if the action is set to Redirect.
  - Forward: The back-end pool of virtual server instances to which the request is forwarded, if the action is set to Forward to pool.
- On the Policies page, you can also create an HTTPS redirect policy with the following configuration:
  - Name: Enter a name for the policy, such as my-policy. The name must be unique within the listener.
  - Action: Select the Redirect to HTTPS option.
  - HTTPS listener: The target HTTPS listener which the traffic from the current HTTP listener will redirect to. Note that you will only see a list of HTTPS listeners whose accept_proxy_proxy value is the same as the HTTP listener.
  - Redirect URI (optional): The URL to which the request redirects.
  - Status code: The status code of the response returned by the load balancer.
- On the Policies page, click Add rule for your policy. If rules exist for the policy, click the value in the Rules column to add more rules.
- In the Rules window, click Add rule and specify the following information to create a rule. If you create multiple rules for a policy, the policy is applied only when all its rules are matched.
  - Condition: Specifies the condition with which a rule is evaluated.
  - Type: The type of information to be evaluated by the rule: the name of the host from which the request originated, an HTTP header field, or a path in the URL.
  - Value: The value to be matched.
  - Key: The name of the HTTP header field to evaluate, if the rule type is Header. For example, to match a cookie in the HTTP header, enter Cookie for the key.

Creating an application load balancer from the CLI

The following example illustrates using the CLI to create an Application Load Balancer for VPC (ALB). In this example, it is in front of one VPC virtual server instance (ID 0716_6acdd058-4607-4463-af08-d4999d983945) running a TCP server that listens on port 9090. The load balancer has a front-end listener, which allows secure access to the TCP server.

To create an application load balancer from the CLI, follow these steps:

Set up your CLI environment.
Use the terminal to log in to your account using the CLI. After you enter the password, the system prompts which account and region you want to use:
```
ibmcloud login --sso
```

Create a load balancer:

ibmcloud is load-balancer-create alb-test public --subnet 0896-b1f24514-89dc-4afd-b0e2-5489a43cf45c --family application

Sample output:

Creating load balancer nlb-test in resource group under account IBM Cloud Network Services as user test@ibm.com...

ID                 r006-99b5ab45-6357-42db-8b32-5d2c8aa62776
Name               alb-test
CRN                crn:v1:public:is:us-south-1:a/123456::load-balancer:r006-99b5ab45-6357-42db-8b32-5d2c8aa62776
Family             Network
Host name          99b5ab45-us-south.lb.test.appdomain.cloud
Subnets            ID                                          Name
                   0896-b1f24514-89dc-4afd-b0e2-5489a43cf45c   nlb

Public IPs
Private IPs
Provision status   create_pending
Operating status   offline
Is public          true
Listeners
Pools              ID   Name

Resource group     ID                                 Name
                   3021f90279574ce287dd5fba82c08899   Default

Created            2020-08-27T14:34:34.732-05:00

Create a pool:

ibmcloud is load-balancer-pool-create alb-pool r006-99b5ab45-6357-42db-8b32-5d2c8aa62776  weighted_round_robin tcp 10

Sample output:

Creating pool nlb-pool of load balancer r006-99b5ab45-6357-42db-8b32-5d2c8aa62776  under account IBM Cloud Network Services as user test@ibm.com...

ID                         r006-3b66d605-6aa5-4166-9f66-b16054da3cb0
Name                       alb-pool
Protocol                   tcp
Algorithm                  weighted_round_robin
Instance group             ID   Name
                           -    -

Health monitor             Type   Port   Health monitor URL   Delay   Retries   Timeout
                           http   8080   /                    10      2         5

Session persistence type   source_ip
Members
Provision status           active
Created                    2020-08-27T14:45:42.038-05:00

Create a member:

ibmcloud is load-balancer-pool-member-create r006-99b5ab45-6357-42db-8b32-5d2c8aa62776 r006-3b66d605-6aa5-4166-9f66-b16054da3cb0 9090 0716_6acdd058-4607-4463-af08-d4999d983945 --weight 70

Sample output:

Creating member of pool r006-3b66d605-6aa5-4166-9f66-b16054da3cb0 under account IBM Cloud Network Services as user test@ibm.com...

ID                 r006-61f8b000-a90d-4abe-909e-c507dffec565
Port               9090
Target             0716_6acdd058-4607-4463-af08-d4999d983945
Weight             70
Health             unknown
Created            2020-08-27T14:59:55.446-05:00
Provision status   create_pending

Create a listener:

ibmcloud is load-balancer-listener-create r006-99b5ab45-6357-42db-8b32-5d2c8aa62776 7070 tcp --default-pool r006-3b66d605-6aa5-4166-9f66-b16054da3cb0

Sample output:

Creating listener of load balancer r006-99b5ab45-6357-42db-8b32-5d2c8aa62776 under account IBM Cloud Network Services as user test@ibm.com...

ID                      r006-2847a948-f9b6-4fc1-91c6-f1c49dac3eba
Certificate instance    -
Connection limit        -
Idle connection timeout 50
Port                    7070
Protocol                tcp
Default pool            r006-3b66d605-6aa5-4166-9f66-b16054da3cb0
Provision status        create_pending
Created                 2020-08-27T15:16:08.643-05:00

Get details about your load balancer:

ibmcloud is load-balancer r006-99b5ab45-6357-42db-8b32-5d2c8aa62776

Sample output:

Getting load balancer r006-99b5ab45-6357-42db-8b32-5d2c8aa62776 under account IBM Cloud Network Services as user test@ibm.com...

ID                 r006-99b5ab45-6357-42db-8b32-5d2c8aa62776
Name               nlb-test
CRN                crn:v1:public:is:us-south-1:a/123456::load-balancer:r006-99b5ab45-6357-42db-8b32-5d2c8aa62776
Family             Network
Host name          99b5ab45-us-south.lb.test.appdomain.cloud
Subnets            ID                                          Name
                   0896-b1f24514-89dc-4afd-b0e2-5489a43cf45c   nlb

Public IPs         150.238.50.78, 150.238.54.95
Private IPs        10.240.0.58, 10.240.0.59
Provision status   active
Operating status   online
Is public          true
Listeners          r006-2847a948-f9b6-4fc1-91c6-f1c49dac3eba
Pools              ID                                          Name
                   r006-3b66d605-6aa5-4166-9f66-b16054da3cb0   nlb-pool

Resource group     ID                                 Name
                   3021f90279574ce287dd5fba82c08899   Default

Created            2020-08-27T14:34:34.732-05:00

Creating an application load balancer with the API

The following example illustrates using the API to create an application load balancer in front of two VPC virtual server instances (192.168.100.5 and 192.168.100.6) running a web application that listens on port 80. The load balancer has a front-end listener, which allows secure access to the web application by using HTTPS.

The example skips the prerequisite steps for using the API to provision a VPC, subnets, and instances.

To create an application load balancer with the API, follow these steps:

Set up your API environment.
Store the following values in variables to be used in the API command:
- ResourceGroupId - First, get your resource group and then populate the variable:
```
export ResourceGroupId=<your_resourcegroup_id>
```

Create a load balancer with a listener, pool, and attached server instances (pool members)

curl -H "Authorization: $iam_token" -X POST
"$vpc_api_endpoint/v1/load_balancers?version=$api_version&generation=2" \
  -d '{
      "name": "example-balancer",
      "is_public": true,
      "listeners": [
          {
              "certificate_instance": {
                  "crn": "crn:v1:bluemix:public:cloudcerts:us-south:a/123456:b8877ea4-b8eg-467e-912a-da1eb7f031cg:certificate:43219c4c97d013fb2a95b21dddde1234"
              },
              "port": 443,
              "protocol": "tcp",
              "default_pool": {
                  "name": "example-pool"
              }
          }
      ],
      "pools": [
          {
              "algorithm": "round_robin",
              "health_monitor": {
                  "delay": 5,
                  "max_retries": 2,
                  "timeout": 2,
                  "type": "tcp",
                  "url_path": "/"
              },
              "name": "example-pool",
              "protocol": "tcp",
              "session_persistence": {
                  "cookie_name": "string",
                  "type": "source_ip"
              },
              "members": [
                  {
                      "port": 80,
                      "target": {
                          "address": "192.168.100.5"
                      },
                      "weight": 50
                  },
                  {
                      "port": 80,
                      "target": {
                          "address": "192.168.100.6"
                      },
                      "weight": 50
                  }
              ]
          }
      ],
      "subnets": [
          {
              "id": "7ec87131-1c7e-4990-b4f0-a26f2e61f98e"
          }
      ]
      }'

Sample output:

{
    "created_at": "2018-07-12T23:17:07.5985381Z",
    "crn": "crn:v1:bluemix:public:is:us-south:a/123456::load-balancer:dd754295-e9e0-4c9d-bf6c-58fbc59e5727",
    "hostname": "ac34687d.lb.appdomain.cloud",
    "href": "https://us-south.iaas.cloud.ibm.com/v1/load_balancers/dd754295-e9e0-4c9d-bf6c-58fbc59e5727",
    "id": "0738-dd754295-e9e0-4c9d-bf6c-58fbc59e5727",
    "is_public": true,
    "profile": {
        "name": "network-fixed",
        "family": "network"
    },
    "listeners": [
        {
            "id": "0738-70294e14-4e61-11e8-bcf4-0242ac110004",
            "href": "https://us-south.iaas.cloud.ibm.com/v1/load_balancers/dd754295-e9e0-4c9d-bf6c-58fbc59e5727/listeners/70294e14-4e61-11e8-bcf4-0242ac110004"
        }
    ],
    "name": "example-balancer",
    "operating_status": "offline",
    "pools": [
        {
            "id": "0738-70294e14-4e61-11e8-bcf4-0242ac110004",
            "href": "https://us-south.iaas.cloud.ibm.com/v1/load_balancers/dd754295-e9e0-4c9d-bf6c-58fbc59e5727/pools/70294e14-4e61-11e8-bcf4-0242ac110004",
            "name": "example-pool"
        }
    ],
    "provisioning_status": "create_pending",
    "resource_group": {
        "id": "56969d60-43e9-465c-883c-b9f7363e78e8"
    },
    "subnets": [
        {
            "id": "0738-7ec86020-1c6e-4889-b3f0-a15f2e50f87e",
            "href": "https://us-south.iaas.cloud.ibm.com/v1/subnets/7ec86020-1c6e-4889-b3f0-a15f2e50f87e",
            "name": "example-subnet"
        }
    ]
}

Save the ID of the load balancer to use in the next steps. For example, save it in the variable lbid.

lbid=0738-dd754295-e9e0-4c9d-bf6c-58fbc59e5727

Get details about the load balancer

curl -H "Authorization: $iam_token" -X GET "$vpc_api_endpoint/v1/load_balancers/$lbid?version=$api_version&generation=2"

Allow some time for provisioning. When the load balancer is ready, it is set to online and active status, as shown in the following sample output:

{
  "id": "0738-dd754295-e9e0-4c9d-bf6c-58fbc59e5727",
  "crn": "crn:v1:bluemix:public:is:us-south:a/123456::load-balancer:dd754295-e9e0-4c9d-bf6c-58fbc59e5727",
  "href": "https://us-south.iaas.cloud.ibm.com/v1/load_balancers/dd754295-e9e0-4c9d-bf6c-58fbc59e5727",
  "name": "example-balancer",
  "created_at": "2018-07-13T22:22:24.489Z",
  "hostname": "dd754295-e9e0-4c9d-bf6c-58fbc59e5727.lb.appdomain.cloud",
  "is_public": true,
  "profile": {
        "name": "network-fixed",
        "family": "network"
  },
  "listeners": [
    {
      "id": "0738-70294e14-4e61-11e8-bcf4-0242ac110004",
       "href": "https://us-south.iaas.cloud.ibm.com/v1/load_balancers/dd754295-e9e0-4c9d-bf6c-58fbc59e5727/listeners/70294e14-4e61-11e8-bcf4-0242ac110004"
    }
  ],
  "operating_status": "online",
  "pools": [
    {
      "id": "0738-70294e14-4e61-11e8-bcf4-0242ac110004",
      "href": "https://us-south.iaas.cloud.ibm.com/v1/load_balancers/dd754295-e9e0-4c9d-bf6c-58fbc59e5727/pools/70294e14-4e61-11e8-bcf4-0242ac110004",
      "name": "example-pool"
    }
  ],
  "private_ips": [
    {
      "address": "192.168.10.5"
    },
    {
      "address": "192.168.10.6"
    }
  ],
  "provisioning_status": "active",
  "public_ips": [
    {
        "address": "169.11.111.115"
    },
    {
        "address": "169.11.111.116"
    }
  ],
  "resource_group": {
    "id": "0738-56969d60-43e9-465c-883c-b9f7363e78e8"
  },
  "subnets": [
    {
      "id": "0738-7ec86020-1c6e-4889-b3f0-a15f2e50f87e",
      "href": "https://us-south.iaas.cloud.ibm.com/v1/subnets/7ec86020-1c6e-4889-b3f0-a15f2e50f87e",
      "name": "example-subnet"
    }
  ]
}