You can use node(‘!master’) or agent { label ‘!master’ } syntax.
https://jenkins.io/doc/pipeline/steps/workflow-durable-task-step/
node: Allocate node
Allocates an executor on a node (typically a slave) and runs further code in the context of a workspace on that slave.
Computer name, label name, or any other label expression like linux && 64bit to restrict where this step builds. May be left blank, in which case any available executor is taken.
Supported operators
The following operators are supported, in descending order of precedence:
(expression)
parentheses — used to explicitly define the associativity of an expression
!expression
NOT — negation; the result of expression must not be true
a && b
AND — both of the expressions a and b must be true
a || b
OR — either of the expressions a or b may be true
a -> b
「implies」 operator — equivalent to !a || b.
For example, windows -> x64 could be thought of as 「if a Windows agent is used, then that agent must be 64-bit」, while still allowing this block to be executed on any agents that do not have the windows label, regardless of whether they have also have an x64 label
a <-> b
「if and only if」 operator — equivalent to a && b || !a && !b
For example, windows <-> dc2 could be thought of as 「if a Windows agent is used, then that agent must be in datacenter 2, but if a non-Windows agent is used, then it must not be in datacenter 2」
Notes
master
This block may be executed only on the Jenkins master
linux-machine-42
This block may be executed only on the agent with the name linux-machine-42 (or on any machine that happens to have a label called linux-machine-42)
windows && jdk9
This block may be executed only on any Windows agent that has version 9 of the Java Development Kit installed (assuming that agents with JDK 9 installed have been given a jdk9 label)
postgres && !vm && (linux || freebsd)
This block may be executed only any on Linux or FreeBSD agent, so long as they are not a virtual machine, and they have PostgreSQL installed (assuming that each agent has the appropriate labels — in particular, each agent running in a virtual machine must have the vm label in order for this example to work as expected)