Monday, 30 October 2017

IBM Cloud Private - Docker, Ubuntu and Volumes

So this week I'm tinkering ( I love that word ) with IBM Cloud Private (ICP), and am planning to install the Community Edition (CE) variant on an Ubuntu VM on my Mac.

This is what I have: -
  • macOS 10.13 High Sierra
  • VMware Fusion 10.0.1
  • Ubuntu 17.10
  • Docker 17.0.6.1-ce
  • IBM Cloud Private 2.1.0
and I'm following the ICP installation from here: -


Having pulled the image: -

sudo docker pull ibmcom/icp-inception:2.1.0

Having previously created a target installation directory: -

sudo mkdir /opt/ibm-cloud-private-ce-2.1.0

and changed to that directory: -

cd /opt/ibm-cloud-private-ce-2.1.0

I then tried to start the image: -

sudo docker run -e LICENSE=accept \
  -v "$(pwd)":/data ibmcom/icp-inception:2.1.0 cp -r cluster /data

However, this didn't appear to do anything :-( 

I then dug further in: -

sudo bash
cd /opt/ibm-cloud-private-ce-2.1.0
docker run -e LICENSE=accept \
  -v "$(pwd)":/data ibmcom/icp-inception:2.1.0 cp -r cluster /data

which returned: -

docker: Error response from daemon: error while creating mount source path '/opt/ibm-cloud-private-ce-2.1.0': mkdir /opt/ibm-cloud-private-ce-2.1.0: read-only file system.

This made no sense, given that I'm effectively running as root :-(

I experimented further: -

docker run -it -v /opt/ibm-cloud-private-ce-2.1.0:/data -e LICENSE=accept ibmcom/icp-inception:2.1.0 /bin/bash

which resulted in much the same: -

docker: Error response from daemon: error while creating mount source path '/opt/ibm-cloud-private-ce-2.1.0': mkdir /opt/ibm-cloud-private-ce-2.1.0: read-only file system.

So, for the record, the switch -v /opt/ibm-cloud-private-ce-2.1.0:/data means that the local OS path ( /opt/ibm-cloud-private-ce-2.1.0 ) is being mapped to the local-to-the-container path ( /data ).

I Googled about a bit: -


which made me wonder whether the problem was with the location, rather than the permissions of the target directory.

I tested this theory: -

mkdir ~/ibm-cloud-private-ce-2.1.0
cd ~/ibm-cloud-private-ce-2.1.0
sudo docker run -e LICENSE=accept \
  -v "$(pwd)":/data ibmcom/icp-inception:2.1.0 cp -r cluster /data

This worked without error, and I was able to confirm that the last part of the command: -

cp -r cluster /data

( which copies data OUT of the container INTO the local filesystem, as mapped using the -v switch )

This is how I validated it: -

pwd

/home/dave/ibm-cloud-private-ce-2.1.0

ls ~/ibm-cloud-private-ce-2.1.0/ -R

/home/dave/ibm-cloud-private-ce-2.1.0/:
cluster

/home/dave/ibm-cloud-private-ce-2.1.0/cluster:
config.yaml  hosts  misc  ssh_key

/home/dave/ibm-cloud-private-ce-2.1.0/cluster/misc:
ldap  storage_class

/home/dave/ibm-cloud-private-ce-2.1.0/cluster/misc/ldap:
cacert  keystone.ldap.conf

/home/dave/ibm-cloud-private-ce-2.1.0/cluster/misc/ldap/cacert:

/home/dave/ibm-cloud-private-ce-2.1.0/cluster/misc/storage_class:

So, the moral of the story appears to be that, for Docker on Ubuntu, it's not possible to map volumes from a container to a directory that's NOT in the user's home directory.

I'll dig further …..

Meantime, I can now continue with my ICP implementation ...

For the record, here's how I checked the versions on the Ubuntu VM: -

lsb_release -a

No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 17.10
Release: 17.10
Codename: artful


docker images

ibmcom/icp-inception   2.1.0               fa65473d72d8        7 days ago          445 MB

docker version

Client:
 Version:      1.13.1
 API version:  1.26
 Go version:   go1.8.3
 Git commit:   092cba3
 Built:        Thu Oct 12 22:34:44 2017
 OS/Arch:      linux/amd64

Server:
 Version:      17.06.1-ce
 API version:  1.30 (minimum version 1.12)
 Go version:   go1.8.3
 Git commit:   5ff8f9c
 Built:        Fri Aug 18 14:48:14 2017
 OS/Arch:      linux/amd64
 Experimental: false

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