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#!/usr/bin/env python3 |
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# "Have-A-Port" | ephemeral port picker for LoadBalancer-type Kubernetes services in clusters with a single-address external address pool |
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from kubernetes import client, config |
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import random |
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SVC_TYPE = 'LoadBalancer' |
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# load client configuration (kubeconfig) |
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config.load_kube_config() |
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# establish API connection |
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connection = client.CoreV1Api() |
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# query service objects |
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all_services = connection.list_service_for_all_namespaces(watch=False) |
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# determine ports in use |
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ports_per_svc = [ svc.spec.ports for svc in all_services.items if svc.spec.type == SVC_TYPE] |
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used_ports = [svc_port.port for svc_ports in ports_per_svc for svc_port in svc_ports] |
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# determine available ports |
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full_port_range = (range(49152, 65536)) # https://tools.ietf.org/html/rfc6335#section-8.1.2 |
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available_ports = list(set(full_port_range) - set(used_ports)) |
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# pick an available port |
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print(random.choice(available_ports)) |