淺談Docker-compose中的depends_on順序的問題解決
使用depends_on進(jìn)行容器排序時(shí)并不能完美的解決容器之間的依賴問題,原因是因?yàn)?depends_on只能保證容器進(jìn)入到 運(yùn)行狀態(tài)而不是完全狀態(tài)(不知道怎么描述了)。
網(wǎng)上已經(jīng)列出來了解決方法,使用 wait-for-it或者 wait-for,在啟動(dòng)時(shí)對需要優(yōu)先啟動(dòng)的容器進(jìn)行訪問,當(dāng)可以訪問成功時(shí)在啟動(dòng),但是都不夠詳細(xì),甚至很多都是同樣的內(nèi)容,(這里吐槽一下環(huán)境真亂)。
可能我比較笨,花了一天才解決,在這里記錄下來。
我使用的是 wait-for
,wait-for-it.sh
我測試的時(shí)候了出現(xiàn)了保錯(cuò)所以沒用。
正文:
需求是要將一個(gè) 打包好的 ar文件注冊到nacos中,但是nacos啟動(dòng)較慢,就需要進(jìn)行順序的設(shè)置。
將需要的 jar文件刪除到虛擬機(jī)或服務(wù)器。接下來編寫 dockerfile
和docker-compose
FROM openjdk:8-jre // 基于 openjdk COPY wait-for . // 將 wait-for 拷貝到虛擬機(jī)中 RUN apt-get update // 更新源, RUN apt-get install netcat -y // 安裝 netcat, wait-for 需要使用到 WORKDIR /app // 設(shè)置落腳點(diǎn) ADD course.jar course.jar // 將 jar 文件 添加到 虛擬機(jī)中 EXPOSE 8002 // 需要暴露的端口
我的配置是以圖片為準(zhǔn)的,代碼塊中的是為了更好的理解 ,想來應(yīng)該沒有差別。
docker-compose
version: '3.0' services: nacos: image: nacos/nacos-server:1.1.4 container_name: nacos ports: - "8848:8848" environment: MODE: standalone # nacos 單節(jié)點(diǎn)運(yùn)行 course: build: /root/ container_name: course ports: - "18002:18002" depends_on: - nacos command: ["sh","wait-for","nacos:8848","--","java","-jar","course.jar"]
這里就不做過多的解釋了,與平常相差不大。
我之前查找到的帖子中,沒有貼出dockerfile文件在這里最重要的就是,將 wait-for
文件拷貝到虛擬機(jī)中,因?yàn)樵?docker-compose
中配置的command所使用的 文件是容器中的,如果你沒有拷貝那么將找不到文件。然后是 apt-get update
和 apt-get install netcat -y
則是安裝 wait-for
運(yùn)行的環(huán)境
我的wait-for
代碼,26行為超時(shí)時(shí)間,剛開始是15,但是時(shí)間太短了 容器超時(shí)我就設(shè)置為了 60,這是我唯一跟原來不一樣的地方,之后就可以測試運(yùn)行了
#!/bin/sh # The MIT License (MIT) # # Copyright (c) 2017 Eficode Oy # # Permission is hereby granted, free of charge, to any person obtaining a copy # of this software and associated documentation files (the "Software"), to deal # in the Software without restriction, including without limitation the rights # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell # copies of the Software, and to permit persons to whom the Software is # furnished to do so, subject to the following conditions: # # The above copyright notice and this permission notice shall be included in all # copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE # SOFTWARE. set -- "$@" -- "$TIMEOUT" "$QUIET" "$PROTOCOL" "$HOST" "$PORT" "$result" TIMEOUT=60 QUIET=0 # The protocol to make the request with, either "tcp" or "http" PROTOCOL="tcp" echoerr() { if [ "$QUIET" -ne 1 ]; then printf "%s\n" "$*" 1>&2; fi } usage() { exitcode="$1" cat << USAGE >&2 Usage: $0 host:port|url [-t timeout] [-- command args] -q | --quiet Do not output any status messages -t TIMEOUT | --timeout=timeout Timeout in seconds, zero for no timeout -- COMMAND ARGS Execute command with args after the test finishes USAGE exit "$exitcode" } wait_for() { case "$PROTOCOL" in tcp) if ! command -v nc >/dev/null; then echoerr 'nc command is missing!' exit 1 fi ;; wget) if ! command -v wget >/dev/null; then echoerr 'wget command is missing!' exit 1 fi ;; esac while :; do case "$PROTOCOL" in tcp) nc -w 1 -z "$HOST" "$PORT" > /dev/null 2>&1 ;; http) wget --timeout=1 -q "$HOST" -O /dev/null > /dev/null 2>&1 ;; *) echoerr "Unknown protocol '$PROTOCOL'" exit 1 ;; esac result=$? if [ $result -eq 0 ] ; then if [ $# -gt 7 ] ; then for result in $(seq $(($# - 7))); do result=$1 shift set -- "$@" "$result" done TIMEOUT=$2 QUIET=$3 PROTOCOL=$4 HOST=$5 PORT=$6 result=$7 shift 7 exec "$@" fi exit 0 fi if [ "$TIMEOUT" -le 0 ]; then break fi TIMEOUT=$((TIMEOUT - 1)) sleep 1 done echo "Operation timed out" >&2 exit 1 } while :; do case "$1" in http://*|https://*) HOST="$1" PROTOCOL="http" shift 1 ;; *:* ) HOST=$(printf "%s\n" "$1"| cut -d : -f 1) PORT=$(printf "%s\n" "$1"| cut -d : -f 2) shift 1 ;; -q | --quiet) QUIET=1 shift 1 ;; -q-*) QUIET=0 echoerr "Unknown option: $1" usage 1 ;; -q*) QUIET=1 result=$1 shift 1 set -- -"${result#-q}" "$@" ;; -t | --timeout) TIMEOUT="$2" shift 2 ;; -t*) TIMEOUT="${1#-t}" shift 1 ;; --timeout=*) TIMEOUT="${1#*=}" shift 1 ;; --) shift break ;; --help) usage 0 ;; -*) QUIET=0 echoerr "Unknown option: $1" usage 1 ;; *) QUIET=0 echoerr "Unknown argument: $1" usage 1 ;; esac done if ! [ "$TIMEOUT" -ge 0 ] 2>/dev/null; then echoerr "Error: invalid timeout '$TIMEOUT'" usage 3 fi case "$PROTOCOL" in tcp) if [ "$HOST" = "" ] || [ "$PORT" = "" ]; then echoerr "Error: you need to provide a host and port to test." usage 2 fi ;; http) if [ "$HOST" = "" ]; then echoerr "Error: you need to provide a host to test." usage 2 fi ;; esac wait_for "$@"
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