An Example to Demonstrate Container Configuration 1.2¶

This tutorial show how to work with container configuration.

In this tutorial you will learn:

How to use the Veea Shell to export container configuration using WebDAV
How to mount the WebDAV-exported configuration on an Ubuntu development machine
How to share configuration files between the development machine and the container running on the VeeaHub

All images on the VeeaHub have access to an image-specific configuration directory that can be populated with files that can be read by your application.

Within the container, the directory is mapped to /usr/local/config/defaults. This example presents an application that reads a file from this directory, and also show how to populate this directory from your development machine.

Creating¶

The first step is to create an instance of the vh_config template.

CODE

$ vhc image create template vh_config
Creating image directory vh_config
Downloaded vh_config.zip
Unzipped vh_config.zip into vh_config

You can view the Dockerfile using the cat utility.

CODE

$ cat Dockerfile
################################################################################
## Copyright (C) Veea Systems Limited - All Rights Reserved.
## Unauthorised copying of this file, via any medium is strictly prohibited.
## Proprietary and confidential. [2019-2020]
################################################################################

ARG ARCH
FROM golang:1.8-alpine as build

RUN mkdir /app
COPY src/ /app/
WORKDIR /app

ARG GOARCH
RUN CGO_ENABLED=0 GOOS=linux GOARCH=$GOARCH go build -a -o goapp
FROM $ARCH/busybox

EXPOSE 9500
ENV PORT 9500

WORKDIR /app/bin
COPY --from=build /app/goapp .

CMD ["/app/bin/goapp"]

You can also view the config.yaml file using cat.

CODE

$ cat config.yaml 
app: vh_config
app_info:
  description: Sample golang web server that demostrates using the configuration volume
  node_types:
  - MEN
  platforms:
    arm32v7:
    - iesv0.5
    - iesv2.5
    arm64v8:
    - iesv0.9
    - iesv1.0
  version: 1.0.0
docker:
  build_opts_arm32v7: --build-arg GOARCH=arm
  build_opts_arm64v8: --build-arg GOARCH=arm64
  ports:
    publish:
    - 9500:9500
  secure:
    arg:
      partner_features: []
    label:
      devices: []
      features:
      - DEVELOPER
      unauth_host: true
      uuid: FFFFFFFF-B819-44D0-8AB5-96992EDD8AA5
      volumes:
        offers: []
        persists: []
        requests: []
version: 3

Notice the architecture-specific Docker build options.

Building¶

CODE

$ vhc image build save --arch arm32v7 --unauth
Saving arm32v7
Generating: /home/joeuser/vh_config/build/unauth/Dockerfile
/home/joeuser/vh_config/build/unauth/Dockerfile is newer than the vh_config-arm32v7:1.0.0 docker image.
Compiling image: vh_config arm32v7
docker build  --build-arg ARCH=arm32v7 --build-arg GOARCH=arm -t vh_config-arm32v7:1.0.0 -f /home/joeuser/vh_config/build/unauth/Dockerfile /home/joeuser/vh_config
Sending build context to Docker daemon  26.11kB
Step 1/22 : ARG ARCH GOARCH
Step 2/22 : FROM golang:1.8-alpine as build
 ---> 4cb86d3661bf
Step 3/22 : RUN mkdir /app
 ---> Running in 12882e544a11
Removing intermediate container 12882e544a11
 ---> acc0fe3d4152
Step 4/22 : COPY src/ /app/
 ---> cb145adf4d07
Step 5/22 : WORKDIR /app
 ---> Running in c2d0f1519c11
Removing intermediate container c2d0f1519c11
 ---> f58fed56113e
Step 6/22 : RUN CGO_ENABLED=0 GOOS=linux GOARCH=$GOARCH go build -a -o goapp
 ---> Running in d45a61daad4d
Removing intermediate container d45a61daad4d
 ---> 9f4c060e50a5
Step 7/22 : FROM $ARCH/busybox
 ---> 451d98dc262d
Step 8/22 : EXPOSE 9500
 ---> Using cache
 ---> c4ee5a301f3e
Step 9/22 : ENV PORT 9500
 ---> Using cache
 ---> 594e42562991
Step 10/22 : WORKDIR /app/bin
 ---> Using cache
 ---> 67bcadfe7592
Step 11/22 : COPY --from=build /app/goapp .
 ---> 4abc5875609d
Step 12/22 : ARG ARCH
 ---> [Warning] The requested image's platform (linux/arm/v7) does not match the detected host platform (linux/amd64) and no specific platform was requested
 ---> Running in d194f2d98f9b
Removing intermediate container d194f2d98f9b
 ---> e7aad4770de3
Step 13/22 : LABEL com.veea.vhc.architecture="$ARCH"
 ---> [Warning] The requested image's platform (linux/arm/v7) does not match the detected host platform (linux/amd64) and no specific platform was requested
 ---> Running in 0ae26cdd7d14
Removing intermediate container 0ae26cdd7d14
 ---> b275a2e4f830
Step 14/22 : LABEL com.veea.vhc.version="1.0.0"
 ---> [Warning] The requested image's platform (linux/arm/v7) does not match the detected host platform (linux/amd64) and no specific platform was requested
 ---> Running in 7b1182734bc7
Removing intermediate container 7b1182734bc7
 ---> 4bd482243c4c
Step 15/22 : LABEL com.veea.vhc.app.name="vh_config"
 ---> [Warning] The requested image's platform (linux/arm/v7) does not match the detected host platform (linux/amd64) and no specific platform was requested
 ---> Running in 7740be9b0b6a
Removing intermediate container 7740be9b0b6a
 ---> bd1a29bbf410
Step 16/22 : LABEL com.veea.vhc.app.version="1.0.0"
 ---> [Warning] The requested image's platform (linux/arm/v7) does not match the detected host platform (linux/amd64) and no specific platform was requested
 ---> Running in 5fbe396ffc76
Removing intermediate container 5fbe396ffc76
 ---> d29ba3d4e635
Step 17/22 : LABEL com.veea.vhc.config.proj.version="3"
 ---> [Warning] The requested image's platform (linux/arm/v7) does not match the detected host platform (linux/amd64) and no specific platform was requested
 ---> Running in 2054c1077bfd
Removing intermediate container 2054c1077bfd
 ---> defed1c509d6
Step 18/22 : LABEL com.veea.vhc.config.user.version="3"
 ---> [Warning] The requested image's platform (linux/arm/v7) does not match the detected host platform (linux/amd64) and no specific platform was requested
 ---> Running in a26c2d297016
Removing intermediate container a26c2d297016
 ---> 32f4fdd9ef2e
Step 19/22 : LABEL com.veea.image.persistent_uuid="FFFFFFFF-B819-44D0-8AB5-96992EDD8AA5"
 ---> [Warning] The requested image's platform (linux/arm/v7) does not match the detected host platform (linux/amd64) and no specific platform was requested
 ---> Running in 1aef156296b3
Removing intermediate container 1aef156296b3
 ---> 9bfdc4cddf2b
Step 20/22 : LABEL com.veea.authorisation.allowOnUnauthenticatedHost="true"
 ---> [Warning] The requested image's platform (linux/arm/v7) does not match the detected host platform (linux/amd64) and no specific platform was requested
 ---> Running in a78c1aebcc76
Removing intermediate container a78c1aebcc76
 ---> 52fb5390265f
Step 21/22 : LABEL com.veea.authorisation.feature1="DEVELOPER"
 ---> [Warning] The requested image's platform (linux/arm/v7) does not match the detected host platform (linux/amd64) and no specific platform was requested
 ---> Running in 4df6bff65827
Removing intermediate container 4df6bff65827
 ---> cb7a67c6c50e
Step 22/22 : CMD ["/app/bin/goapp"]
 ---> [Warning] The requested image's platform (linux/arm/v7) does not match the detected host platform (linux/amd64) and no specific platform was requested
 ---> Running in c05b3163889e
Removing intermediate container c05b3163889e
 ---> 2b6636e08a38
Successfully built 2b6636e08a38
Successfully tagged vh_config-arm32v7:1.0.0
Pruning any dangling instances of the same image
Saving: vh_config arm32v7
  Writing vh_config-arm32v7:1.0.0.unsigned.tar

Running¶

Uploading¶

Upload the image archive to the VeeaHub using the vhc hub access upload-image command.

CODE

$ vhc hub access upload-image build/unauth/arm32v7/vh_config-arm32v7\:1.0.0.unsigned.tar 
Creating image push for file [build/unauth/arm32v7/vh_config-arm32v7:1.0.0.unsigned.tar] on C25CTW00000000001567:9000 (images/push)...
##################################################################################################################################### 100.0%

Log into the Veea Shell and check that the image was imported correctly.

CODE

$ vhc hub access shell

                  **      **   ********  **      **
                 /**     /**  **//////  /**     /**
                 /**     /** /**        /**     /**
                 //**    **  /********* /**********
                  //**  **   ////////** /**//////**
                   //****           /** /**     /**
                    //**      ********  /**     /**
                     //      ////////   //      //

    Welcome to the Veea shell.   Type help or ? to list commands.

[VHC25000001567-FFFFFFFF]

CODE

[VHC25000001567-FFFFFFFF] docker image ls
REPOSITORY          | TAG     | ID             | P-UUID                                 | CREATED          | SIZE     
vh_config-arm32v7   | 1.0.0   | 272850b4b1d2   | FFFFFFFF-F9DE-4663-B68E-6AC14F429805   | 45 minutes ago   | 59.09MB  
[VHC25000001567-FFFFFFFF]

Create the Container¶

CODE

[VHC25000001567-FFFFFFFF] docker image create vh_config:1.0.0:272850b4 --detach --publish-all
8d4eeea90f81c43de77427413c1ceb1d2d5bff42dd85c45b74cdc23157c11547
[VHC25000001567-FFFFFFFF]

Don’t forget to include the --publish-all flag to publish the exposed TCP port 9500.

Export the Config Volume¶

CODE

[VHC25000001567-FFFFFFFF] docker container export vh_config:1.0.0:272850b4
Configuration exported on https://<ip-address>:9002
[VHC25000001567-FFFFFFFF]

Mount the Config Volume¶

One your development machine, run:

CODE

$ sudo mount -t davfs https://192.168.10.176:9002 /mnt
Please enter the username to authenticate with server
https://192.168.10.176:9002 or hit enter for none.
  Username: 
Please enter the password to authenticate user  with server
https://192.168.10.176:9002 or hit enter for none.
  Password:  
/sbin/mount.davfs: the server certificate does not match the server name
/sbin/mount.davfs: the server certificate is not trusted
  issuer:      0, Veea Inc
  subject:     0, Veea Inc
  identity:    C25CTW00000000001567.devices.veea.io
  fingerprint: 4b:28:a8:78:a1:b1:a8:e6:5c:15:59:b1:e2:04:7a:ce:85:c8:fe:40
You only should accept this certificate, if you can
verify the fingerprint! The server might be faked
or there might be a man-in-the-middle-attack.
Accept certificate for this session? [y,N] y
/sbin/mount.davfs: warning: the server does not support locks

If the mount fails with the following message:

mount: /mnt: unknown filesystem type 'davfs'.

then you need to install the davfs2 package using:

sudo apt-get install davfs2

Update the Configuration¶

CODE

$ sudo cp assets/config.json /mnt
$ sync; sync

Look at the contents of the file and notice the values:

CODE

$ jq . assets/config.json
{
  "welcome": "Welcome to the VeeaHub platform!",
  "bool_param": true,
  "int_param": 10005200,
  "string_param": "Don't string me along!"
}

Start the Container¶

In the Veea Shell, run:

CODE

[VHC25000001567-FFFFFFFF] docker container start vh_config:1.0.0:272850b4
2587418d75a3067ddd82e0299ad938acc8d5c48eaf56de3db4f27bd36fa78a0d
[VHC25000001567-FFFFFFFF]

View the Config File¶

CODE

[VHC25000001567-FFFFFFFF] docker container exec vh_config:1.0.0:272850b4 /bin/sh
/app/bin $ cat /usr/local/config/defaults/config.json 
{
  "welcome": "Welcome to the VeeaHub platform!",
  "bool_param" : true,
  "int_param" : 10005200,
  "string_param" : "Don't string me along!"
}

View the Web Server Output¶

On the development machine, run:

CODE

$ curl http://192.168.10.176:9500
<H1>Welcome to the VeeaHub platform!</H1>
<H2>Configuration from '/usr/local/config/defaults/config.json'</H2>
welcome: "Welcome to the VeeaHub platform!"<br>
bool_param: true<br>
int_param: 10005200<br>
string_param: "Don't string me along!"<br>

You can see that the values match those of the config.json file.

Alternately, you can use a web browser to view the HTML output.

Unmount the Config Volume¶

To unmount the config volume, run:

CODE

$ sudo umount /mnt
/sbin/umount.davfs: waiting while mount.davfs (pid 28547) synchronizes the cache .. OK

Unexport the Config Volume¶

In the Veea Shell, run:

CODE

[VHC25000001567-00000033] docker container unexport vh_config:1.0.0:272850b4
[VHC25000001567-00000033]

The will shutdown the WebDAV server to stop exporting the config volume.