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89 lines
2.6 KiB
Bash
89 lines
2.6 KiB
Bash
#!/usr/bin/env bash
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# vim:ts=4:sts=4:sw=4:et
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#
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# Author: Hari Sekhon
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# Date: 2021-04-16 17:44:30 +0100 (Fri, 16 Apr 2021)
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#
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# https://github.com/HariSekhon/bash-tools
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#
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# License: see accompanying Hari Sekhon LICENSE file
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#
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# If you're using my code you're welcome to connect with me on LinkedIn and optionally send me feedback to help steer this or other code I publish
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#
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# https://www.linkedin.com/in/HariSekhon
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#
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set -euo pipefail
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[ -n "${DEBUG:-}" ] && set -x
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srcdir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
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# shellcheck disable=SC1090
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. "$srcdir/lib/utils.sh"
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# shellcheck disable=SC2034,SC2154
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usage_description="
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Drains all Kubernetes nodes from a given GKE cluster's nodepool
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Useful to decommission an entire nodepool to delete or recreate it (eg. with different taints)
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You must have a second node pool with sufficient capacity / autoscaling max nodes to be able to accommodate the evicted pods
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- finds instance groups in a node pool
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- finds nodes in each instance group
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- disables autoscaling for the node pool (to prevent booting new nodes to migrate pods to)
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- cordons all nodes (to prevent pod migrations to other nodes in the same pool)
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- drains pods from each node in sequence
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Requires:
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- GCloud SDK to be installed and configured
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- requires core/project and compute/region to be set in your gcloud config
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or else environment variables CLOUDSDK_CORE_PROJECT and CLOUDSDK_COMPUTE_REGION
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- uses adjacent scripts:
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- gke_nodepool_nodes2.sh - lists all nodes in the given nodepool
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- gke_kubectl.sh - for safe kubectl with isolated context
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If gcloud config container/cluster or CLOUDSDK_CONTAINER_CLUSTER are set then you don't have to specify the cluster name
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"
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# used by usage() in lib/utils.sh
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# shellcheck disable=SC2034
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usage_args="[<cluster_name>] <node_pool_name>"
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help_usage "$@"
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min_args 1 "$@"
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if [ $# -eq 2 ]; then
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export GCLOUD_CONTAINER_CLUSTER="$1"
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node_pool="$2"
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elif [ $# -eq 1 ]; then
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node_pool="$1"
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else
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usage
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fi
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nodes="$(VERBOSE=1 "$srcdir/gke_nodepool_nodes2.sh" "$node_pool")"
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echo >&2
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timestamp "disabling autoscaling for node pool '$node_pool'"
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gcloud container node-pools update --no-enable-autoscaling "$node_pool"
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echo >&2
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timestamp "cordoning nodes:"
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for node in $nodes; do
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#timestamp "cordoning node '$node'"
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"$srcdir/gke_kubectl.sh" cordon "$node"
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done
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force=""
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if [ "${FORCE:-1}" ]; then
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force="--force"
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fi
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for node in $nodes; do
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echo >&2
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timestamp "draining node '$node'"
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"$srcdir/gke_kubectl.sh" drain "$node" $force --ignore-daemonsets # & # could parallelize this - respects pod disruption budgets
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done
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