mirror of https://github.com/apache/lucene.git
166 lines
4.5 KiB
Bash
Executable File
166 lines
4.5 KiB
Bash
Executable File
#!/bin/bash
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#
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# A helper script to wait for ZooKeeper
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#
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# This script waits for a ZooKeeper master to appear.
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# It repeatedly looks up the name passed as argument
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# in the DNS using getent, and then connects to the
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# ZooKeeper admin port and uses the 'srvr' command to
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# obtain the server's status.
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# You can use this in a Kubernetes init container to
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# delay Solr pods starting until the ZooKeeper service
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# has settled down. Or you could explicitly run this in
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# the Solr container before exec'ing Solr.
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#
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# Inspired by https://github.com/helm/charts/blob/9eba7b1c80990233a68dce48f4a8fe0baf9b7fa5/incubator/solr/templates/statefulset.yaml#L60
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#
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# Usage: wait-for-zookeeper.sh [--max-attempts count] [--wait-seconds seconds] zookeeper-service-name
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#
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# If no argument is provided, but a Solr-style ZK_HOST is set,
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# that will be used. If neither is provided, the default
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# name is 'solr-zookeeper-headless', to match the helm chart.
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set -euo pipefail
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SCRIPT="$0"
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if [[ "${VERBOSE:-}" == "yes" ]]; then
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set -x
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fi
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function usage {
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echo "$1"
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echo "Usage: $SCRIPT [--max-attempts count] [--wait-seconds seconds ] zookeeper-service-name"
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exit 1
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}
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TMP_HOSTS="/tmp/hosts.$$"
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TMP_STATUS="/tmp/status.$$"
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function cleanup {
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rm -f $TMP_HOSTS $TMP_STATUS
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}
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trap cleanup EXIT
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function check_zookeeper {
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local host=$1
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local port="${2:-2181}"
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if ! echo srvr | nc "$host" "$port" > $TMP_STATUS; then
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echo "Failed to get status from $host"
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return
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fi
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if [ ! -s $TMP_STATUS ]; then
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echo "No data from $ip"
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return
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fi
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if grep -q 'not currently serving requests' $TMP_STATUS; then
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echo "Node $ip is not currently serving requests"
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return
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fi
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mode=$(grep "Mode: " $TMP_STATUS | sed 's/Mode: //');
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if [ -z "$mode" ]; then
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echo "Cannot determine mode from:"
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cat $TMP_STATUS
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return
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fi
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echo "Node $ip is a $mode"
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if [ "$mode" = "leader" ] || [ "$mode" = "standalone" ]; then
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echo "Done"
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exit 0
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fi
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}
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max_attempts=120
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wait_seconds=2
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while (( $# > 0 )); do
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case "$1" in
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--help)
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cat <<EOM
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Usage: $SCRIPT [options] zookeeper-service-name
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Options:
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--max-attempts count: number of attempts to check Solr is up. Default: $max_attempts
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--wait-seconds seconds: number of seconds to wait between attempts. Default: $wait_seconds
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EOM
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exit 0
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;;
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--max-attempts)
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max_attempts="$2";
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shift 2;
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;;
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--wait-seconds)
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wait_seconds="$2";
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shift 2;
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;;
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*)
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if [ -n "${lookup_arg:-}" ]; then
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usage "Cannot specify multiple zookeeper service names"
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fi
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lookup_arg=$1;
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shift;
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break;
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;;
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esac
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done
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grep -q -E '^[0-9]+$' <<<"$max_attempts" || usage "--max-attempts $max_attempts: not a number"
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if (( max_attempts == 0 )); then
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echo "The --max-attempts argument should be >0"
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exit 1
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fi
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grep -q -E '^[0-9]+$' <<<"$wait_seconds" || usage "--wait-seconds $wait_seconds: not a number"
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if [ -z "${lookup_arg:-}" ]; then
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if [ -n "$ZK_HOST" ]; then
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lookup_arg="$ZK_HOST"
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else
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lookup_arg=solr-zookeeper-headless
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fi
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fi
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echo "Looking up '$lookup_arg'"
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# split on commas, for when a ZK_HOST string like zoo1:2181,zoo2:2181 is used
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IFS=',' read -ra lookups <<< "$lookup_arg"
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((attempts_left=max_attempts))
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while (( attempts_left > 0 )); do
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for lookup in "${lookups[@]}"; do
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if grep -q -E "^\[[0-9].*\]" <<<"$lookup"; then
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# looks like an IPv6 address, eg [2001:DB8::1] or [2001:DB8::1]:2181
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# getent does not support the bracket notation, but does support IPv6 addresses
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host=$(sed -E 's/\[(.*)\].*/\1/' <<<"$lookup")
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port=$(sed -E 's/^\[(.*)\]:?//' <<<"$lookup")
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else
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# IPv4, just split on :
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IFS=: read -ra split <<<"$lookup"
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host="${split[0]}"
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port="${split[1]:-}"
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fi
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if [[ "${VERBOSE:-}" == "yes" ]]; then
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echo "Parsed host=$host port=${port:-}"
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fi
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if getent hosts "$host" > $TMP_HOSTS; then
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while read -r ip hostname ; do
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echo "${hostname:-}">/dev/null # consume for shellcheck
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check_zookeeper "$ip" "$port"
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done <$TMP_HOSTS
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else
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echo "Cannot find $lookup yet"
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fi
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done
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(( attempts_left-- ))
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if (( attempts_left == 0 )); then echo "Still no master found; giving up"
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exit 1
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fi
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sleep "$wait_seconds"
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done
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# To test the parsing:
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# bash scripts/wait-for-zookeeper.sh foo
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# bash scripts/wait-for-zookeeper.sh 'ZK_HOST=[2001:DB8::1]:2181,[2001:DB8::1],127.0.0.1:2181,127.0.0.2'
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# ZK_HOST=[2001:DB8::1]:2181,[2001:DB8::1],127.0.0.1:2181,127.0.0.2 bash scripts/wait-for-zookeeper.sh
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