etcd on tmpfs

etcd

ETCD_LISTEN_CLIENT_URLS=https://0.0.0.0:2379
ETCD_ADVERTISE_CLIENT_URLS=https://<replace-with-your-own>
ETCD_CERT_FILE=<replace-with-your-own>
ETCD_KEY_FILE=<replace-with-your-own>
ETCD_CA_FILE=<replace-with-your-own>

etcd-helper.sh

#!/bin/bash

do_snapshot() {
    sleep 10
    env
    while true
    do
        (set -x; etcdctl --endpoints="$ETCD_ADVERTISE_CLIENT_URLS" --cacert="$ETCD_CA_FILE" --cert="$ETCD_CERT_FILE" --key="$ETCD_KEY_FILE" snapshot save "$HELPER_SNAPSHOT_DIR"/$(date +%s).db)
        (cd "$HELPER_BACKUP_DIR" && ls -tp | grep -v '/$' | tail -n +100 | xargs -d '\n' rm -- {})
        sleep 60;
    done
}

do_backup() {
    epoch=$(stat --printf='%Y' /var/lib/etcd/current/member/snap/db)
    (set -x; cp /var/lib/etcd/current/member/snap/db "$HELPER_BACKUP_DIR"/"$epoch".db)
}

do_restore() {
    if [[ $(find "$HELPER_SNAPSHOT_DIR" -name '*.db' -print | wc -l) == "0" ]]; then
        echo "no snapshot exists, quit"
        exit 0
        # TODO: init ?
    fi
    if [[ -e ${ETCD_DATA_DIR}/member/snap ]]; then
        echo "file exists, skip restore from snapshot"
        exit 0
    fi
    latest=$(find "$HELPER_SNAPSHOT_DIR" -name '*.db' -print0 | xargs -r -0 ls -1 -t | head -1)
    (set -x; etcdutl snapshot restore "$latest" --data-dir "$ETCD_DATA_DIR" --skip-hash-check)
}

case $1 in
    start)
        do_snapshot &
        exec etcd
    ;;
    restore)
        do_restore
    ;;
    backup)
        do_backup
    ;;
    *)
        echo "Usage: $0 {snapshot|restore|backup}"
        exit 1
    ;;
esac;

etcd.service

[Unit]
Description=etcd key-value store
Documentation=https://github.com/etcd-io/etcd
After=network-online.target local-fs.target remote-fs.target time-sync.target
Wants=network-online.target local-fs.target remote-fs.target time-sync.target
RequiresMountsFor=/var/lib/etcd/current/
ConditionPathIsMountPoint=/var/lib/etcd/current/

[Service]
User=root
Type=notify
Environment=ETCD_DATA_DIR=/var/lib/etcd/current/
Environment=ETCD_NAME=%m
Environment=HELPER_SNAPSHOT_DIR=/var/lib/etcd/snapshots/
EnvironmentFile=/etc/default/etcd
ExecStartPre=/usr/local/bin/etcd-helper.sh restore
ExecStart=/usr/local/bin/etcd-helper.sh start
ExecStopPost=/usr/local/bin/etcd-helper.sh backup
Restart=always
RestartSec=10s
LimitNOFILE=40000

[Install]
WantedBy=multi-user.target