Ubuntu – Apt-cacher-ng not responcible to vm-client

apt-cacher-ngvirtual

I did not manage to get apt-cacher-ng working in network.
I wonder which of all its prerequisites are still not fulfilled (?)
Maybe someone will come with deciding hint.
Furthermore, while on troubleshooting several questions arise on my side.
Also, few facts are suggesting it is the apt-cacher-ng issue rather than networking.

Below the situation description:
computer A: virtual machine with apt-cacher-ng installed and in operation.
computer B: quite regular virtual machine connects to comp. A instead of
going to public repository for package installation/update.

Those two virt machines run on one single physical host and for both Ubuntu 15.10 is used as guest OS; used virtualization solution is VmWare Fusion. Both virt. machines use Fusion Internet Sharing for network connection. apt-cacher-ng was installed using Ubuntu's package management. Package management claims it is the 0.8.5-1ubuntu0.1 version. No customization was made on apt-cacher-ng, except for CacheDir setting.
Firewall is off on computer A.
Comp B' apt-get is configured in following way: /etc/apt/apt.conf.d/01proxy, the file 01proxy reads a single line Acquire::http::Proxy "http://ip6-<comp-A-ip>:3142";

Problem:
Comp B is not able to connect to apt-cacher-ng, sudo apt-get update gets hanged in very beginning when the message reads connecting to ip6-comp-A-ip:3142.End of problem

However, following is working fine
All the achieved is merely to update / install packages on computer A through apt-cacher-ng.
No problems when comp B connects to public repositories directly and bypassing apt-cacher-ng.
If to start samba server on computer A and setup a file share then to connect to this share from computer B all works fine.
Also computer B can successfully ping comp A.
Physical host can successfully ping comp A too.
Also it is possible to have Firefox on comp B and open http://<comp-A-ip>:3142/acng-report.html>.
End of stuff working fine

Daemon is started by init.d with command line option pointing to socket path.
That's the point where I have to wonder, because working local client (same virt. machine) is using comp A' ip address, not a socket.

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Ubuntu – Install oracle-java7-installer through apt-cacher-ng

I was just battling with this, here are my findings for Ubuntu 14.04 Trusty Tahr.

The installer uses apt-config to determine which proxy to use. Specifically if Acquire::http::Proxy::download.oracle.com returns DIRECT to determine whether to use the default proxy of to download directly.

Specifically the install runs

# use apt proxy
APT_PROXIES=$(apt-config shell \
http_proxy Acquire::http::Proxy \
https_proxy Acquire::https::Proxy \
ftp_proxy Acquire::ftp::Proxy \
dl_direct Acquire::http::Proxy::download.oracle.com \
)

And later on

if [ "$dl_direct" = "DIRECT" ]; then
    unset http_proxy
    unset https_proxy
    unset ftp_proxy
fi

If you use the following apt config then the installer with download directly:

Acquire::http::Proxy "http://my.proxy.com:3142";
Acquire::http::Proxy {
        download.oracle.com DIRECT;
};

While this works it is somewhat annoying as the download takes forever and that somewhat defeats the purpose of the proxy.

I found that the installer checks a debconf variable to check whether to use a local file. The property checked is oracle-java8-installer/local and it is a string.

Specifically the installer runs:

db_get oracle-java8-installer/local
if [ -d "$RET" -a -f "$RET"/$FILENAME ]; then

    echo "Installing from local file $RET/$FILENAME"
    cp -f -p "$RET"/$FILENAME ${FILENAME}_TEMP
    mv -f ${FILENAME}_TEMP $FILENAME
else # no local file

So if you have the JDK downloaded and in a directory /jdk/dir then you need to run the following command before running the installer:

sudo debconf-set-selections <<< 'debconf oracle-java8-installer/local string /jdk/dir/'

Note the trailing / on the directory - this is required.

Ubuntu – Howto use apt-cacher-ng only when available

Something like this should work:

/etc/NetworkManager/dispatcher.d

#!/bin/bash
ip=10.0.1.13
port=3142
nc -w 1 $ip $port
proxy_file="/etc/apt/apt.conf.d/02local_proxy"
if [ $? -eq 0 ]; then
    echo "Acquire::http { Proxy \"http://$ip:$port\"; };" > $proxy_file
    echo 'Acquire::https { Proxy "false"; };' >> $proxy_file
else
    rm -f $proxy_file
fi

Fix permissions

sudo chmod +x /etc/NetworkManager/dispatcher.d/99SetAptProxy

Notes:

The "nc" command tests that it can connect to the 3142 port on the given IP address.
This script is run everytime the networking interfaces are changed by network manager.
Feel free to alter the way that you detect for the proxy, this works for me, but it is a security vulnerability if you install packages on a foreign network, for example.

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Related Solutions

Ubuntu – Install oracle-java7-installer through apt-cacher-ng

Ubuntu – Howto use apt-cacher-ng only when available

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