The Operator is the primary user of the HostRule CRD. The CRD is used to express additional virtual host properties. The virtual host FQDN is matched from either the Kubernetes ingress or OpenShift route-based objects.

Note:

With AKO version 1.11.1, HostRule is transitioned to version v1beta1. There are no schema changes between version v1alpha1 and v1beta1. AKO 1.11.1 supports both versions v1alpha1and v1beta1. However, it is recommended to create new CRD objects in v1beta1 and transition the existing objects to this version.

AKO will deprecate v1alpha1 in the upcoming releases.

A sample HostRule CRD looks as shown below:

apiVersion: ako.vmware.com/v1beta1
kind: HostRule
metadata:
  name: my-host-rule
  namespace: red
spec:
  virtualhost:
    fqdn: foo.region1.com # mandatory
    fqdnType: Exact
    enableVirtualHost: true
    tls: # optional
      sslKeyCertificate:
        name: avi-ssl-key-cert
        type: ref
        alternateCertificate:
          name: avi-ssl-key-cert2
          type: ref
      sslProfile: avi-ssl-profile
      termination: edge
    gslb:
      fqdn: foo.com
      includeAliases: false
    httpPolicy: 
      policySets:
      - avi-secure-policy-ref
      overwrite: false
    datascripts:
    - avi-datascript-redirect-app1
    wafPolicy: avi-waf-policy
    applicationProfile: avi-app-ref
    icapProfile: 
    - avi-icap-ref
    analyticsProfile: avi-analytics-ref
    errorPageProfile: avi-errorpage-ref
    analyticsPolicy: # optional
      fullClientLogs:
        enabled: true
        throttle: HIGH
      logAllHeaders: true
    tcpSettings:
      listeners:
      - port: 8081
      - port: 6443
        enableSSL: true
      loadBalancerIP: 10.10.10.1
    aliases: # optional
    -  bar.com
    -  baz.com

Usage of HostRule

HostRule CRD can be created in a given namespace where the operator requires better control. This section explains the details and associated rules of using each field of the HostRule CRD.

HostRule to Virtual Service Matching Using FQDN/FQDNType

A given HostRule is applied to a virtual service if the virtual service hosts the FQDN mentioned in the HostRule CRD. This FQDN must exactly match the one the virtual service is hosting. However, to simplify the user experience and provide an easy way to apply a HostRule to an individual or multiple virtual services, the FQDNType field can be employed. It provides great flexibility when it comes to specifying the string in the FQDN field.

With the FQDN Type, one of the three matching criteria listed below can be specified:

  • Exact: Matches the string character by character to the virtual service FQDNs in an exact match fashion.

  • Wildcard: Matches the string to multiple virtual service FQDNs and matches the FQDNs with the provided string as the suffix. The string must start with a * to qualify for wildcard matching.

    fqdn: *.alb.vmware.com     
fqdnType: Wildcard

  • Contains: Matches the string to multiple virtual service FQDNs and matches the FQDNs with the provided string as a substring of any possible FQDNs programmed by AKO.

    fqdn: Shared-VS-L7-1   
fqdnType: Contains

    The fqdnType field defaults to Exact.

Enable/Disable Virtual Host

HostRule CRD can be used to activate/deactivate corresponding virtual services created by AKO on VMware NSX Advanced Load Balancer. This removes any virtual host related configuration from the data plane (VMware NSX Advanced Load Balancer Service Engines) in addition to deactivating traffic on the virtual host/FQDN.

enableVirtualHost: false

This property can be applied only for secure FQDNs and cannot be applied for insecure routes. The default value is true.

Express httppolicyset Object Refs

HostRule CRD can be used to express httppolicyset references.

Note:

The httppolicyset objects must be pre-created in the NSX Advanced Load Balancer Controller.

     httpPolicy: 
       policySets:
       - "avi-secure-policy-ref"
       overwrite: false

The httppolicyset currently is only applicable for secure FQDNs and cannot be applied for insecure routes. The order of evaluation of the httppolicyset rules is in the same order they appear in the CRD definition. The list of httppolicyset rules is always intepreted as an AND operation.

AKO currently uses httppolicyset objects on the SNI virtual services to route traffic based on host/path matches. These rules are always at a lower index than the httppolicyset objects specified in the CRD object. If a user wants to overwrite all httppolicyset objects on an SNI virtual service with the ones specified in the HostRule CRD, the overwrite flag can be set to true. The default value for overwrite is false.

Express WAF Policy Object Refs

HostRule CRD can be used to express WAF policy references. Create the WAF policy object in the NSX Advanced Load Balancer Controller prior to the CRD creation as follows:

wafPolicy: "avi-waf-policy"

Note:

This property can be applied only for secure FQDNs and cannot be applied for insecure routes. WAF policies are useful when deep layer 7 packet filtering is required.

Express Custom Application Profiles

HostRule CRD can be used to express application profile references. Create the application profile reference in the NSX Advanced Load Balancer Controller prior to the CRD creation. The application profile must be of Type APPLICATION_PROFILE_TYPE_HTTP.

applicationProfile: "my-app-ref"

Note:

This property can be applied only for secure FQDNs and cannot be applied for insecure routes. The application profiles can be used for various HTTP/HTTP2 protocol settings.

Express Custom ICAP profile

HostRule CRD can be used to express a single ICAP profile reference per host. The ICAP profile reference must have been created in the NSX Advanced Load Balancer Controller prior to this CRD creation.

icapProfile:
- avi-icap-ref

This property can be applied for both secure and insecure hosts through EVH parent and child virtual services, SNI child Virtual Services, and dedicated virtual services. The ICAP Profile can be used for transporting HTTP traffic to 3rd party services for processes such as content sanitization and antivirus scanning. For more information, see Internet Content Adaptation Protocol topic in the VMware NSX Advanced Load Balancer Configuration Guide

Express Custom Analytics Profiles

HostRule CRD is used to express analytics profile references.Create the analytics profile reference in the NSX Advanced Load Balancer Controller prior to this CRD creation.

analyticsProfile: avi-analytics-ref`

Note:

This property can be applied only for secure FQDNs and cannot be applied for insecure routes. The analytics profiles can be used for various Network/HTTP/Health score analytics settings, log processing, and so on.

Express Custom Error Page Profiles

HostRule CRD can be used to express error page profile references.Create the error page profile reference in the NSX Advanced Load Balancer Controller prior to this CRD creation.

errorPageProfile: avi-errorpage-ref

Note:

This property can be applied only for secure FQDNs and cannot be applied for insecure routes. The error page profiles can be used to send a custom error page to the client generated by the proxy.

Express DataScripts

HostRule CRD can be used to express error DataScript references.Create the DataScript references in the NSX Advanced Load Balancer Controller prior to this CRD creation.

datascripts:    
- avi-datascript-redirect-app1
Note:

This property can be applied only for secure FQDNs and cannot be applied for insecure routes. The DataScripts can be used to apply custom scripts to data traffic. The order of evaluation of the DataScripts is in the same order they appear in the CRD definition.

Express TLS Configuration

For the AKO to control the TLS termination from a privileged namespace, the HostRule CRD can be created in such a namespace.

    tls:
      sslKeyCertificate:
        name: avi-ssl-key-cert
        type: ref
        alternateCertificate:
          name: avi-ssl-key-cert2
          type: ref
      sslProfile: avi-ssl-profile
      termination: edge

Here, name refers to an VMware NSX Advanced Load Balancer object with the Type as ref. Alternatively, we also support a kubernetes Secret to be specified where the sslkeyandcertificate object is created by AKO using the Secret.

    tls:
      sslKeyCertificate:
        name: k8s-app-secret
        type: secret
      termination: edge
Note:

Currently, only Edge is supported as the type of termination.

An alternateCertificate option is provided if the application needs to be configured to provide multiple server certificates, typically when trying to configure both RSA and ECC signed certificates. The NSX Advanced Load Balancer Controller allows a virtual service to be configured with two certificates at a time, one each of RSA and ECC. This enables the Controller to negotiate the optimal algorithm or cipher with the client. If the client supports ECC, the ECC algorithm is preferred, and RSA is used as a fallback in cases where the clients do not support ECC.

The sslProfile, additionally, can be used to determine the set of SSL versions and ciphers to accept for SSL/TLS terminated connections. If the sslProfile is not defined, AKO defaults to the sslProfileSystem-Standard-PFS defined in VMware NSX Advanced Load Balancer.

Configure GSLB FQDN

A GSLB FQDN can be specified within the HostRule CRD. This is only used if AKO is used with AMKO and not otherwise.

gslb:       
     fqdn: foo.com

This additional FQDN inherits all the properties of the root FQDN specified under the virtualHost section. Use this flag if you would want traffic with a GSLB FQDN to get routed to a site local FQDN. For example, in the above CRD, the client request from a GSLB DNS will arrive with the host header as foo.com to the VIP hosting foo.region1.com in region1. This CRD property would ensure that the request is routed appropriately to the backend service of foo.region1.com.

This knob is currently supported only with the SNI model and not with Enhanced Virtual Hosting model. The includeAliases is used by AMKO. Whenever a GSLB FQDN is provided, and the useCustomGlobalFqdn is set to true in AMKO, a GSLB Service is created for the GSLB FQDN instead of the local FQDN(hostname). For more information, see Deriving GslbService FQDNs topic in the Avi Multi-Cluster Kubernetes Operator Guide.

When this flag is set to false, the Domain Name of the GSLB Service is set to the GSLB FQDN. When this flag is set to true in addition to the GSLB FQDN, AMKO adds the FQDNs mentioned under aliases to domain names of the GSLB Service.

Configure Aliases for FQDN

The Aliases field adds the ability to have multiple FQDNs configured under a specific route/ingress for the child virtual service instead of creating the route/ingress multiple times.

aliases: 
        - bar.com   
        - baz.com

This list of FQDNs inherits all the properties of the root FQDN specified under the virtualHost section. Traffic arrives with the host header as bar.com to the VIP hosting foo.region1.com and this CRD property would ensure that the request is routed appropriately to the backend service of foo.region1.com.

Aliases field must contain unique FQDNs and must not contain GSLB FQDN or the root FQDN. Users must ensure that the fqdnType is set as Exact before setting this field.

Configure Analytics Policy

The HostRule CRD can be used to configure analytics policies such as enable/disable non-significant logs, throttle the number of non-significant logs per second on each SE, enable/disable logging of all headers, and, so on:

 analyticsPolicy:
  fullClientLogs:
    enabled: true
    throttle: HIGH
   logAllHeaders: true

The throttle will be in effect only when enabled is set to true. The possible values of throttle are DISABLED (0), LOW (50), MEDIUM (30), and HIGH (10).

AKO sets the duration of logging the non-significant logs to infinity by default.It is recommended to deactivate the non-significant logs when it is no longer required.

Configure TCP Settings

The TCP Settings section is responsible for configuring Parent virtual service specific parameters using the HostRule CRD. The tcpSettings block, in addition to any other parameters provided in the HostRule, is only applied to Parent virtual services and dedicated virtual services.

The tcpSettings block does not have any effect on child VSes. To consume TCP setting configurations for parent virtual services, the HostRule must be matched to a Shared/Dedicated VS FQDN, using the existing fqdn field in HostRule. When dedicated virtual services are created corresponding to a single application, shared virtual services host multiple application FQDNs. Therefore, to apply a HostRule to a dedicated VS, users can simply provide the application FQDN in the HostRule fqdn field. For Shared virtual services, users can either provide the AKO programmed shared virtual service FQDN, or utilize the fqdnType: Contains parameter with the Shared virtual service name itself.

fqdn: foo.com     # dedicated VS
    fqdnType: Exact
    tcpSetting:
      listeners:
      - port: 6443
        enableSSL: true


    fqdn: Shared-VS-L7-1.admin.avi.com    # AKO configured Shared VS fqdn
    fqdnType: Exact
    tcpSetting:
      loadBalancerIP: 10.10.10.1


    fqdn: Shared-VS-L7-1      # bound for clusterName--Shared-VS-L7-1
    fqdnType: Contains
    tcpSetting:
      loadBalancerIP: 10.10.10.1

Custom Ports: To overwrite the ports opened for the virtual services created by AKO, users can provide the port details under the listeners setting. The ports mentioned under this section overwrite the default open ports, 80 and 443 (SSL enabled). This is applicable only for Shared or Dedicated virtual services.

    tcpSettings:
      listeners:
      - port: 80
      - port: 8081
      - port: 6443
        enableSSL: true
Note:

  • At least one of the ports that are mentioned in the setting must have the enableSSL field set to true.

  • If enableHTTP2 is set to true, then the HTTP2 traffic will be supported from client to Service Engine.

L7 Static IP: The loadBalancerIP field can be used to provide a valid, preferred IPv4 address for L7 virtual services created for the Shared or Dedicated virtual service. The preferred IP must be part of the IPAM configured for the Cloud, and must not overlap with any other IP addresses already in use. When misconfigurations occur, AKO fails to configure the virtual service, appropriately throwing an ERROR log for the same.

     tcpSettings:  
     loadBalancerIP: 10.10.10.199
Note:

The HostRule CRD is not aware of the misconfigurations while it is being created and so, the HostRule will be accepted.

Status Messages

The status messages are used to give instant feedback about the reference objects specified in the HostRule CRD.

Following are some of the sample status messages:

  1. Accepted HostRule Object:

    $ kubectl get hr
NAME                 HOST                  STATUS     AGE
secure-waf-policy    foo.avi.internal      Accepted   3d3h

    A HostRule is accepted only when all the reference objects specified inside it exist in the NSX Advanced Load Balancer Controller.

  2. A Rejected HostRule Object:

    $ kubectl get hr
NAME                     HOST                  STATUS     AGE
secure-waf-policy-alt    foo.avi.internal      Rejected   2d23h

    The reason for rejection can be obtained from the status:

    status:
error: duplicate fqdn foo.avi.internal found in default/secure-waf-policy-alt
status: Rejected

Caveats

Converting Insecure FQDNs to Secure

The HostRule CRD can be used to convert an insecure host FQDN to a secure one. This is done by specifying a TLS section in the CRD object. The sslKeyCertificate is provided for the FQDN, will override all sslkeyandcertificates generated for the FQDN. This is useful if:

  • The operator wants to convert an insecure ingress FQDN to secure.

  • The operator wants to override any existing secrets for a given host FQDN and define TLS termination semantics.

Certificate Precedence

If the ingress object specifies a secret for SNI termination and the HostRule CRD also specifies a sslKeyCertificate for the same virtualhost, the sslkeycertificate in the HostRule CRD will take precedence over the Secret object associated with the Ingress.

HostRule Deletion

If a HostRule is deleted, all the settings for the FQDNs are withdrawn from the NSX Advanced Load Balancer Controller.

HostRule Admission

A HostRule CRD is only admitted if all the objects referenced in it, exist in the NSX Advanced Load Balancer Controller. If after admission, the object references are deleted out-of-band, the AKO does not re-validate the associated HostRule CRD objects. The user needs to manually edit or delete the object for new changes to take effect.

Duplicate FQDN rules

Two HostRule CRDs cannot be used for the same FQDN information across namespaces. If AKO finds a duplicate FQDN in more than one HostRules, AKO honors the first HostRule that gets created and rejects the others. When AKO reboots occur, the CRD that gets honored might not be the same as the one honored earlier.