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add clarity/fix typos man/docker-build

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add needed clarity for
1)  using STDIN to pass build context
2)  --cpu-shares flag use

also a few typos

Signed-off-by: Sally O'Malley <somalley@redhat.com>
This commit is contained in:
Sally O'Malley 2015-10-02 07:26:13 -04:00
parent 77da5d8feb
commit a2bc804936
1 changed files with 41 additions and 21 deletions
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62
man/docker-build.1.md
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@ -40,8 +40,9 @@ The Docker CLI reports "Sending build context to Docker daemon" when the context
the daemon.
When the URL to a tarball archive or to a single Dockerfile is given, no context is sent from
the client to the Docker daemon. When a Git repository is set as the **URL**, the repository is
cloned locally and then sent as the context.
the client to the Docker daemon. In this case, the Dockerfile at the root of the archive and
the rest of the archive will get used as the context of the build. When a Git repository is
set as the **URL**, the repository is cloned locally and then sent as the context.
# OPTIONS
**-f**, **--file**=*PATH/Dockerfile*
@ -93,32 +94,50 @@ cloned locally and then sent as the context.
**-c**, **--cpu-shares**=*0*
CPU shares (relative weight).
By default, all containers get the same proportion of CPU cycles. You can
change this proportion by adjusting the container's CPU share weighting
relative to the weighting of all other running containers.
By default, all containers get the same proportion of CPU cycles.
CPU shares is a 'relative weight', relative to the default setting of 1024.
This default value is defined here:
```
cat /sys/fs/cgroup/cpu/cpu.shares
1024
```
You can change this proportion by adjusting the container's CPU share
weighting relative to the weighting of all other running containers.
To modify the proportion from the default of 1024, use the **-c** or
**--cpu-shares** flag to set the weighting to 2 or higher.
To modify the proportion from the default of 1024, use the **--cpu-shares**
flag to set the weighting to 2 or higher.
Container CPU share Flag
{C0} 60% of CPU --cpu-shares=614 (614 is 60% of 1024)
{C1} 40% of CPU --cpu-shares=410 (410 is 40% of 1024)
The proportion is only applied when CPU-intensive processes are running.
When tasks in one container are idle, the other containers can use the
left-over CPU time. The actual amount of CPU time used varies depending on
the number of containers running on the system.
For example, consider three containers, one has a cpu-share of 1024 and
two others have a cpu-share setting of 512. When processes in all three
For example, consider three containers, where one has **--cpu-shares=1024** and
two others have **--cpu-shares=512**. When processes in all three
containers attempt to use 100% of CPU, the first container would receive
50% of the total CPU time. If you add a fourth container with a cpu-share
of 1024, the first container only gets 33% of the CPU. The remaining containers
50% of the total CPU time. If you add a fourth container with **--cpu-shares=1024**,
the first container only gets 33% of the CPU. The remaining containers
receive 16.5%, 16.5% and 33% of the CPU.
Container CPU share Flag CPU time
{C0} 100% --cpu-shares=1024 33%
{C1} 50% --cpu-shares=512 16.5%
{C2} 50% --cpu-shares=512 16.5%
{C4} 100% --cpu-shares=1024 33%
On a multi-core system, the shares of CPU time are distributed across the CPU
cores. Even if a container is limited to less than 100% of CPU time, it can
use 100% of each individual CPU core.
For example, consider a system with more than three cores. If you start one
container **{C0}** with **-c=512** running one process, and another container
**{C1}** with **-c=1024** running two processes, this can result in the following
container **{C0}** with **--cpu-shares=512** running one process, and another container
**{C1}** with **--cpu-shares=1024** running two processes, this can result in the following
division of CPU shares:
PID container CPU CPU share
@ -142,7 +161,7 @@ kernel to restrict the container's CPU usage to the quota you specify.
CPUs in which to allow execution (0-3, 0,1).
**--cpuset-mems**=*CPUSET-MEMS*
Memory nodes (MEMs) in which to allow execution (-1-3, 0,1). Only effective on
Memory nodes (MEMs) in which to allow execution (0-3, 0,1). Only effective on
NUMA systems.
For example, if you have four memory nodes on your system (0-3), use `--cpuset-mems=0,1`
@ -204,16 +223,16 @@ name, and tag (where the tag in this context means the qualifier after
the ":"). In this example we build a JBoss image for the Fedora repository
and give it the version 1.0:
docker build -t fedora/jboss:1.0
docker build -t fedora/jboss:1.0 .
The next example is for the "whenry" user repository and uses Fedora and
JBoss and gives it the version 2.1 :
docker build -t whenry/fedora-jboss:v2.1
docker build -t whenry/fedora-jboss:v2.1 .
If you do not provide a version tag then Docker will assign `latest`:
docker build -t whenry/fedora-jboss
docker build -t whenry/fedora-jboss .
When you list the images, the image above will have the tag `latest`.
@ -229,16 +248,17 @@ as context. The Dockerfile at the root of the repository is used as
Dockerfile. This only works if the GitHub repository is a dedicated
repository.
docker build github.com/scollier/Fedora-Dockerfiles/tree/master/apache
docker build github.com/scollier/purpletest
Note: You can set an arbitrary Git repository via the `git://` schema.
## Building an image using a URL to a tarball'ed context
This will send the URL itself to the Docker daemon. The daemon will fetch the
tarball archive, decompress it and use its contents as the build context. If you
pass an *-f PATH/Dockerfile* option as well, the system will look for that file
inside the contents of the tarball.
tarball archive, decompress it and use its contents as the build context. The
Dockerfile at the root of the archive and the rest of the archive will get used
as the context of the build. If you pass an **-f PATH/Dockerfile** option as well,
the system will look for that file inside the contents of the tarball.
docker build -f dev/Dockerfile https://10.10.10.1/docker/context.tar.gz