Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 233)

Brocade Virtual ADX Server Load Balancing Guide 217
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Boolean health checks
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Follow the steps given below to use a health-check policy.
1. Configure the element-action expressions.
2. Configure the health-check policy using element-action expressions and logical expressions
joined by the operators AND or OR or NOT.
3. Attach logical expressions to application ports on specific real servers. A health check policy
does not take effect until you attach it to an application port on a server.
NOTE
A health-check policy does not take effect (begin sending health check packets) until you
attach the policy to an application port on a real server.
Configuring boolean health check
A health-check policy consists of one or more element-action expressions. When a logical
expression contains multiple element-action expressions, the policy also contains the logical
operator AND or OR or NOT. You can use a health-check policy as an element-action expression in
another policy.
To configure a health-check policy, enter commands such as the following.
Virtual ADX(config)#healthck "httpsrvr" boolean
Virtual ADX(config-hc-httpsrvr)#and "check1" "check2"
These commands configure a health-check policy that uses the element-action expressions
"check1" and "check2". Because the AND operator is used, the real servers in both "check1" and
"check2" must reply successfully for the health check to be successful. If only one of the servers
replies, the health check is unsuccessful and the Brocade Virtual ADX stops using all the server
application ports in the health-check policy "httpsrvr".
Syntax: [no] healthck "policy-name" boolean
Syntax: and | or "element-name" "element-name"
The policy-name variable specifies the name of the health-check policy. The name can be up to
20 characters long. The name cannot contain blanks.
The and or or command specifies a logical operator in the health-check policy. You can enter
two element-action expressions along with the logical operator and, or or not.
• If you specify and, the policy evaluates to true only if all elements (IP addresses) respond to the
health check.
• If you specify or, the policy is true if at least one of the elements responds to the health check.
• If you specify not, the policy is true if none of the elements responds to the health check.
If you are configuring a boolean UDP health check policy, define the static next hop MAC address
along with a VLAN ID for on that link; otherwise, the Brocade Virtual ADX cannot learn the
next-hop-mac-address of that link. Enter commands such as the following to define a static
next-hop-mac-address and a VLAN-ID.
Virtual ADX(config-link-link3)#next-hop-mac-address 00e0.5208.dd8e vlan-id 40