Google Jib - 是否可以使用 CMD/ENTRYPOINT 在容器启动时 运行 一个 linux 命令？
Google Jib - Is it possible to run a linux command at container startup using CMD/ENTRYPOINT?
是否可以在容器使用 cmd 或入口点或 jib maven 插件中的任何其他机制从 jib 图像启动时 运行 linux 命令，然后启动 java 进程？
在我的例子中，我想运行这个命令：
echo "127.0.0.1 $HOSTNAME" >> /etc/hosts
你总是可以set a custom entrypoint using <container><entrypoint>。您可以启动一个 shell 脚本，运行 一个不同的程序，等等。有时，您可能想使用 <extraDirectories> 功能来复制一个脚本（并赋予它可执行权限）。
有关 运行 shell 脚本的一些想法，请参阅 ：
Another option is to define your own <entrypoint> to use a shell.
(Therefore, you need a base image that includes a shell binary (such
as /bin/bash). Note that the default base image prior to Jib 3.0 was
Distroless and
did not include a shell program. OTOH, Jib 3.0+ doesn't use
Distroless.)
In this method, you'll need to know the right Java runtime classpath
and the main class to use in your JVM launch command. To help this,
starting with Jib >= 3.1, Jib creates two JVM argument
files
inside a built image; they will hold, respectively, the classpath and
the main class inside a built image.
Knowing the entrypoint, you can write a shell script
(my-entrypoint.sh):
#!/bin/sh
# Assumes `java` is on PATH in the base image.
exec java $JAVA_OPTS \
-cp $( cat /app/jib-classpath-file ) \
$( cat /app/jib-main-class-file )
Alternatively, if you are on Java 9+, you can leverage the @-argument
file:
exec java $JAVA_OPTS -cp @/app/jib-classpath-file @/app/jib-main-class-file
Place my-entrypoint.sh under <project root>/src/main/jib. This is
the default directory for Jib's <extraDirectories> feature, and Jib
will place src/main/jib/my-entrypoint.sh at the root directory in
the container image. Then set the default <entrypoint> to this
script:
<container>
<!-- Assumes you have /bin/sh as specified at the top of /my-entrypoint.sh. -->
<entrypoint>/my-entrypoint.sh</entrypoint>
</container>
<!-- You also need to make the script executable. -->
<extraDirectories>
<permissions>
<permission>
<file>/my-entrypoint.sh</file>
<mode>755</mode>
</permission>
</permissions>
</extraDirectories>
Alternatively, if you invoke /bin/sh as below, you don't have to
configure <extraDirectories> to make the file executable. This may
not look customary; you would normally make the script executable and
run it directly. But this is perfectly valid, and there is no
difference in terms of actual execution (as long as the shebang of
/entrypoint.sh is the same #!/bin/sh).
<container>
<entrypoint>
<arg>/bin/sh</arg>
<arg>/my-entrypoint.sh</arg>
</entrypoint>
</container>
It's also possible to do this without creating a script (basically
embedding the entire script in pom.xml and passing it to a shell
program). In this case, you don't need to configure
<extraDirectories>.
<container>
<entrypoint>
<arg>/bin/sh</arg>
<arg>-c</arg>
<arg>exec java $JAVA_OPTS -cp $( cat /app/jib-classpath-file ) $( cat /app/jib-main-class-file )</arg>
</entrypoint>
</container>
是否可以在容器使用 cmd 或入口点或 jib maven 插件中的任何其他机制从 jib 图像启动时 运行 linux 命令，然后启动 java 进程？
在我的例子中，我想运行这个命令：
echo "127.0.0.1 $HOSTNAME" >> /etc/hosts
你总是可以set a custom entrypoint using <container><entrypoint>。您可以启动一个 shell 脚本，运行 一个不同的程序，等等。有时，您可能想使用 <extraDirectories> 功能来复制一个脚本（并赋予它可执行权限）。
有关 运行 shell 脚本的一些想法，请参阅
Another option is to define your own
<entrypoint>to use a shell. (Therefore, you need a base image that includes a shell binary (such as/bin/bash). Note that the default base image prior to Jib 3.0 was Distroless and did not include a shell program. OTOH, Jib 3.0+ doesn't use Distroless.) In this method, you'll need to know the right Java runtime classpath and the main class to use in your JVM launch command. To help this, starting with Jib >= 3.1, Jib creates two JVM argument files inside a built image; they will hold, respectively, the classpath and the main class inside a built image.Knowing the entrypoint, you can write a shell script (
my-entrypoint.sh):#!/bin/sh # Assumes `java` is on PATH in the base image. exec java $JAVA_OPTS \ -cp $( cat /app/jib-classpath-file ) \ $( cat /app/jib-main-class-file )Alternatively, if you are on Java 9+, you can leverage the @-argument file:
exec java $JAVA_OPTS -cp @/app/jib-classpath-file @/app/jib-main-class-filePlace
my-entrypoint.shunder<project root>/src/main/jib. This is the default directory for Jib's<extraDirectories>feature, and Jib will placesrc/main/jib/my-entrypoint.shat the root directory in the container image. Then set the default<entrypoint>to this script:<container> <!-- Assumes you have /bin/sh as specified at the top of /my-entrypoint.sh. --> <entrypoint>/my-entrypoint.sh</entrypoint> </container> <!-- You also need to make the script executable. --> <extraDirectories> <permissions> <permission> <file>/my-entrypoint.sh</file> <mode>755</mode> </permission> </permissions> </extraDirectories>Alternatively, if you invoke
/bin/shas below, you don't have to configure<extraDirectories>to make the file executable. This may not look customary; you would normally make the script executable and run it directly. But this is perfectly valid, and there is no difference in terms of actual execution (as long as the shebang of/entrypoint.shis the same#!/bin/sh).<container> <entrypoint> <arg>/bin/sh</arg> <arg>/my-entrypoint.sh</arg> </entrypoint> </container>It's also possible to do this without creating a script (basically embedding the entire script in
pom.xmland passing it to a shell program). In this case, you don't need to configure<extraDirectories>.<container> <entrypoint> <arg>/bin/sh</arg> <arg>-c</arg> <arg>exec java $JAVA_OPTS -cp $( cat /app/jib-classpath-file ) $( cat /app/jib-main-class-file )</arg> </entrypoint> </container>