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277 lines
10 KiB
Bash
Executable File
277 lines
10 KiB
Bash
Executable File
#!/usr/bin/env bash
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# Copyright 2014 The Kubernetes Authors.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# LIMITATIONS
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# 1. Exit code is probably not always correct.
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# 2. There are no unittests.
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# 3. Will not work if the total length of paths to addons is greater than
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# bash can handle. Probably it is not a problem: ARG_MAX=2097152 on GCE.
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# cosmetic improvements to be done
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# 1. Improve the log function; add timestamp, file name, etc.
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# 2. Logging doesn't work from files that print things out.
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# 3. Kubectl prints the output to stderr (the output should be captured and then
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# logged)
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KUBECTL=${KUBECTL_BIN:-/usr/local/bin/kubectl}
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KUBECTL_OPTS=${KUBECTL_OPTS:-}
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# KUBECTL_PRUNE_WHITELIST is a list of resources whitelisted by default.
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# This is currently the same with the default in:
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# https://github.com/kubernetes/kubectl/blob/master/pkg/cmd/apply/prune.go.
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# To override the default list with other values, set
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# KUBECTL_PRUNE_WHITELIST_OVERRIDE environment variable to space-separated
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# names of resources to whitelist.
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if [ -z "${KUBECTL_PRUNE_WHITELIST_OVERRIDE:-}" ]; then
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KUBECTL_PRUNE_WHITELIST=(
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core/v1/ConfigMap
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core/v1/Endpoints
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core/v1/Namespace
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core/v1/PersistentVolumeClaim
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core/v1/PersistentVolume
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core/v1/Pod
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core/v1/ReplicationController
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core/v1/Secret
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core/v1/Service
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batch/v1/Job
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batch/v1beta1/CronJob
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apps/v1/DaemonSet
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apps/v1/Deployment
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apps/v1/ReplicaSet
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apps/v1/StatefulSet
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extensions/v1beta1/Ingress
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)
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else
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read -ra KUBECTL_PRUNE_WHITELIST <<< "${KUBECTL_PRUNE_WHITELIST_OVERRIDE}"
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fi
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ADDON_CHECK_INTERVAL_SEC=${TEST_ADDON_CHECK_INTERVAL_SEC:-60}
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ADDON_PATH=${ADDON_PATH:-/etc/kubernetes/addons}
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SYSTEM_NAMESPACE=kube-system
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# Addons could use this label with two modes:
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# - ADDON_MANAGER_LABEL=Reconcile
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# - ADDON_MANAGER_LABEL=EnsureExists
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ADDON_MANAGER_LABEL="addonmanager.kubernetes.io/mode"
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# This label is deprecated (only for Addon Manager). In future release
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# addon-manager may not respect it anymore. Addons with
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# CLUSTER_SERVICE_LABEL=true and without ADDON_MANAGER_LABEL=EnsureExists
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# will be reconciled for now.
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CLUSTER_SERVICE_LABEL="kubernetes.io/cluster-service"
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# Whether only one addon manager should be running in a multi-master setup.
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# Disabling this flag will force all addon managers to assume they are the
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# leaders.
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ADDON_MANAGER_LEADER_ELECTION=${ADDON_MANAGER_LEADER_ELECTION:-true}
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# Remember that you can't log from functions that print some output (because
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# logs are also printed on stdout).
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# $1 level
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# $2 message
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function log() {
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# manage log levels manually here
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# add the timestamp if you find it useful
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case $1 in
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DB3 )
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# echo "$1: $2"
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;;
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DB2 )
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# echo "$1: $2"
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;;
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DBG )
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# echo "$1: $2"
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;;
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INFO )
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echo "$1: $2"
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;;
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WRN )
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echo "$1: $2"
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;;
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ERR )
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echo "$1: $2"
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;;
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* )
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echo "INVALID_LOG_LEVEL $1: $2"
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;;
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esac
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}
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# Generate kubectl prune-whitelist flags from provided resource list.
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function generate_prune_whitelist_flags() {
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local -r resources=( "$@" )
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for resource in "${resources[@]}"; do
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# Check if $resource isn't composed just of whitespaces by replacing ' '
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# with '' and checking whether the resulting string is not empty.
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if [[ -n "${resource// /}" ]]; then
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printf "%s" "--prune-whitelist ${resource} "
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fi
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done
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}
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# KUBECTL_EXTRA_PRUNE_WHITELIST is a list of extra whitelisted resources
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# besides the default ones.
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extra_prune_whitelist=
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if [ -n "${KUBECTL_EXTRA_PRUNE_WHITELIST:-}" ]; then
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read -ra extra_prune_whitelist <<< "${KUBECTL_EXTRA_PRUNE_WHITELIST}"
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fi
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prune_whitelist=( "${KUBECTL_PRUNE_WHITELIST[@]}" "${extra_prune_whitelist[@]}" )
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prune_whitelist_flags=$(generate_prune_whitelist_flags "${prune_whitelist[@]}")
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log INFO "== Generated kubectl prune whitelist flags: $prune_whitelist_flags =="
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# $1 filename of addon to start.
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# $2 count of tries to start the addon.
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# $3 delay in seconds between two consecutive tries
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# $4 namespace
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function start_addon() {
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local -r addon_filename=$1;
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local -r tries=$2;
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local -r delay=$3;
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local -r namespace=$4
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create_resource_from_string "$(cat "${addon_filename}")" "${tries}" "${delay}" "${addon_filename}" "${namespace}"
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}
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# $1 string with json or yaml.
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# $2 count of tries to start the addon.
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# $3 delay in seconds between two consecutive tries
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# $4 name of this object to use when logging about it.
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# $5 namespace for this object
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function create_resource_from_string() {
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local -r config_string=$1;
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local tries=$2;
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local -r delay=$3;
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local -r config_name=$4;
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local -r namespace=$5;
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while [ "${tries}" -gt 0 ]; do
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# shellcheck disable=SC2086
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# Disabling because "${KUBECTL_OPTS}" needs to allow for expansion here
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echo "${config_string}" | ${KUBECTL} ${KUBECTL_OPTS} --namespace="${namespace}" apply -f - && \
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log INFO "== Successfully started ${config_name} in namespace ${namespace} at $(date -Is)" && \
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return 0;
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(( tries-- ))
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log WRN "== Failed to start ${config_name} in namespace ${namespace} at $(date -Is). ${tries} tries remaining. =="
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sleep "${delay}";
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done
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return 1;
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}
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function reconcile_addons() {
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# TODO: Remove the first command in future release.
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# Adding this for backward compatibility. Old addons have CLUSTER_SERVICE_LABEL=true and don't have
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# ADDON_MANAGER_LABEL=EnsureExists will still be reconciled.
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# Filter out `configured` message to not noisily log.
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# `created`, `pruned` and errors will be logged.
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log INFO "== Reconciling with deprecated label =="
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# shellcheck disable=SC2086
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# Disabling because "${KUBECTL_OPTS}" needs to allow for expansion here
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${KUBECTL} ${KUBECTL_OPTS} apply -f ${ADDON_PATH} \
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-l ${CLUSTER_SERVICE_LABEL}=true,${ADDON_MANAGER_LABEL}!=EnsureExists \
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--prune=true ${prune_whitelist_flags} --recursive | grep -v configured
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log INFO "== Reconciling with addon-manager label =="
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# shellcheck disable=SC2086
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# Disabling because "${KUBECTL_OPTS}" needs to allow for expansion here
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${KUBECTL} ${KUBECTL_OPTS} apply -f ${ADDON_PATH} \
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-l ${CLUSTER_SERVICE_LABEL}!=true,${ADDON_MANAGER_LABEL}=Reconcile \
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--prune=true ${prune_whitelist_flags} --recursive | grep -v configured
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log INFO "== Kubernetes addon reconcile completed at $(date -Is) =="
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}
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function ensure_addons() {
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# Create objects already exist should fail.
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# Filter out `AlreadyExists` message to not noisily log.
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# shellcheck disable=SC2086
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# Disabling because "${KUBECTL_OPTS}" needs to allow for expansion here
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${KUBECTL} ${KUBECTL_OPTS} create -f ${ADDON_PATH} \
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-l ${ADDON_MANAGER_LABEL}=EnsureExists --recursive 2>&1 | grep -v AlreadyExists
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log INFO "== Kubernetes addon ensure completed at $(date -Is) =="
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}
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function is_leader() {
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# In multi-master setup, only one addon manager should be running. We use
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# existing leader election in kube-controller-manager instead of implementing
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# a separate mechanism here.
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if ! $ADDON_MANAGER_LEADER_ELECTION; then
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log INFO "Leader election disabled."
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return 0;
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fi
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# shellcheck disable=SC2086
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# Disabling because "${KUBECTL_OPTS}" needs to allow for expansion here
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KUBE_CONTROLLER_MANAGER_LEADER=$(${KUBECTL} ${KUBECTL_OPTS} -n kube-system get ep kube-controller-manager \
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-o go-template=$'{{index .metadata.annotations "control-plane.alpha.kubernetes.io/leader"}}' \
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| sed 's/^.*"holderIdentity":"\([^"]*\)".*/\1/')
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# If there was any problem with getting the leader election results, var will
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# be empty. Since it's better to have multiple addon managers than no addon
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# managers at all, we're going to assume that we're the leader in such case.
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log INFO "Leader is $KUBE_CONTROLLER_MANAGER_LEADER"
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# KUBE_CONTROLLER_MANAGER_LEADER value is in the form "${HOSTNAME}_*"
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# Here we verify that the value is either empty or is in the expected form for the leader
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KUBE_CONTROLLER_MANAGER_LEADER="${KUBE_CONTROLLER_MANAGER_LEADER##${HOSTNAME}_*}"
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[[ "$KUBE_CONTROLLER_MANAGER_LEADER" == "" ]]
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}
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# The business logic for whether a given object should be created
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# was already enforced by salt, and /etc/kubernetes/addons is the
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# managed result of that. Start everything below that directory.
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log INFO "== Kubernetes addon manager started at $(date -Is) with ADDON_CHECK_INTERVAL_SEC=${ADDON_CHECK_INTERVAL_SEC} =="
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# Wait for the default service account to be created in the kube-system namespace.
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token_found=""
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while [ -z "${token_found}" ]; do
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sleep .5
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# shellcheck disable=SC2086
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# Disabling because "${KUBECTL_OPTS}" needs to allow for expansion here
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if ! token_found=$(${KUBECTL} ${KUBECTL_OPTS} get --namespace="${SYSTEM_NAMESPACE}" serviceaccount default -o go-template="{{with index .secrets 0}}{{.name}}{{end}}"); then
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token_found="";
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log WRN "== Error getting default service account, retry in 0.5 second =="
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fi
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done
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log INFO "== Default service account in the ${SYSTEM_NAMESPACE} namespace has token ${token_found} =="
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# Create admission_control objects if defined before any other addon services. If the limits
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# are defined in a namespace other than default, we should still create the limits for the
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# default namespace.
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while IFS=$'\n' read -r obj; do
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start_addon "${obj}" 100 10 default &
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log INFO "++ obj ${obj} is created ++"
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done < <(find /etc/kubernetes/admission-controls \( -name \*.yaml -o -name \*.json \))
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# Start the apply loop.
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# Check if the configuration has changed recently - in case the user
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# created/updated/deleted the files on the master.
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log INFO "== Entering periodical apply loop at $(date -Is) =="
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while true; do
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start_sec=$(date +"%s")
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if is_leader; then
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ensure_addons
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reconcile_addons
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else
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log INFO "Not elected leader, going back to sleep."
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fi
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end_sec=$(date +"%s")
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len_sec=$((end_sec-start_sec))
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# subtract the time passed from the sleep time
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if [[ ${len_sec} -lt ${ADDON_CHECK_INTERVAL_SEC} ]]; then
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sleep_time=$((ADDON_CHECK_INTERVAL_SEC-len_sec))
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sleep ${sleep_time}
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fi
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done
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