updated doc from todo

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bmiast 2025-05-28 07:38:39 +00:00
parent e12ee33245
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3 changed files with 112 additions and 53 deletions

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@ -14,13 +14,13 @@ integration.
Before proceeding, ensure the following:
- Incus is installed on the host system (`sudo apt install incus`).
\- Incus is installed on the host system (`sudo apt install incus`).
- A Debian-based container is created in Incus.
\- A Debian-based container is created in Incus.
- Basic knowledge of Linux networking and container management.
\- Basic knowledge of Linux networking and container management.
- Root or sudo access to the host and container.
\- Root or sudo access to the host and container.
# Step-by-Step Configuration
@ -104,12 +104,12 @@ interfaces named `vA` and `vB`.
This command:
- Creates a `veth` pair with one end (`vA`) in the default namespace
and the other end (`vB`) in the `deb1`'s network namespace.
\- Creates a `veth` pair with one end (`vA`) in the default namespace
and the other end (`vB`) in the `deb1`'s network namespace.
- Ensures the interfaces are set up and operational, allowing network
traffic to flow between the container and the `ns1` namespace (or
default namespace if `ns1` is not explicitly created).
\- Ensures the interfaces are set up and operational, allowing network
traffic to flow between the container and the `ns1` namespace (or
default namespace if `ns1` is not explicitly created).
The script uses the `pyroute2` library to manage network interfaces and
namespaces, and supports container types such as Incus, LXC, LXD, and
@ -184,22 +184,48 @@ Add or modify the following settings to enable DNS and DHCP:
**Explanation:**
- `domain-needed`: Prevents incomplete domain names from being sent to
upstream DNS.
\- `domain-needed`: Prevents incomplete domain names from being sent to
upstream DNS.
- `bogus-priv`: Blocks reverse DNS lookups for private IP ranges.
\- `bogus-priv`: Blocks reverse DNS lookups for private IP ranges.
- `no-resolv`: Disables reading `/etc/resolv.conf`.
\- `no-resolv`: Disables reading `/etc/resolv.conf`.
- `server`: Specifies upstream DNS servers (Google DNS in this case).
\- `server`: Specifies upstream DNS servers (Google DNS in this case).
- `local` and `domain`: Configures a local domain.
\- `local` and `domain`: Configures a local domain.
- `dhcp-range`: Defines the IP range for DHCP clients (from
192.168.1.100 to 192.168.1.200, lease time 12 hours).
\- `dhcp-range`: Defines the IP range for DHCP clients (from
192.168.1.100 to 192.168.1.200, lease time 12 hours).
- `dhcp-option`: Sets the default gateway (option 3) and DNS servers
(option 6).
\- `dhcp-option`: Sets the default gateway (option 3) and DNS servers
(option 6).
## System-Level Adjustments for Network Stability
In some cases, especially in nested or privileged containers, additional
system-level adjustments are necessary to ensure proper network
functionality and avoid conflicts.
To remount the `/sys` filesystem as read-write (required if certain
networking tools fail due to mount restrictions):
``` {.bash language="bash"}
sudo mount -o remount,rw /sys
sudo systemctl restart systemd-udevd
```
Additionally, to prevent DNS conflicts with `systemd-resolved`, which
may interfere with `dnsmasq`, stop and disable the service:
``` {.bash language="bash"}
sudo systemctl stop systemd-resolved
sudo systemctl disable systemd-resolved
```
This ensures that `dnsmasq` can bind to port 53 without conflicts. If
you require `systemd-resolved`, consider configuring it to listen on a
different interface or using socket activation.
## Starting and Enabling dnsmasq
@ -232,12 +258,12 @@ that it receives an IP address in the range
If `dnsmasq` fails to start:
- Check the logs: `incus exec deb1 journalctl -u dnsmasq`.
\- Check the logs: `incus exec deb1 journalctl -u dnsmasq`.
- Ensure no other service is using port 53 (DNS) or 67 (DHCP).
\- Ensure no other service is using port 53 (DNS) or 67 (DHCP).
- Verify the network configuration with `incus exec deb1 ip a` and
`incus exec deb1 ping 8.8.8.8`.
\- Verify the network configuration with `incus exec deb1 ip a` and
`incus exec deb1 ping 8.8.8.8`.
# Conclusion

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@ -44,12 +44,16 @@ This guide provides step-by-step instructions for setting up \texttt{dnsmasq} as
\section{Prerequisites}
Before proceeding, ensure the following:
\begin{itemize}
\item Incus is installed on the host system (\texttt{sudo apt install incus}).
\item A Debian-based container is created in Incus.
\item Basic knowledge of Linux networking and container management.
\item Root or sudo access to the host and container.
\end{itemize}
- Incus is installed on the host system (\texttt{sudo apt install incus}).
- A Debian-based container is created in Incus.
- Basic knowledge of Linux networking and container management.
- Root or sudo access to the host and container.
\section{Step-by-Step Configuration}
@ -64,8 +68,6 @@ incus start deb1
\end{lstlisting}
The \texttt{security.syscalls.intercept.mount}, \texttt{security.nesting}, and \texttt{security.privileged} settings are required for \texttt{dnsmasq} and Docker to function correctly in the container.
% New subsection for firewall settings
\subsection{Firewall Configuration}
To allow traffic forwarding between the \texttt{incusbr0} bridge and the \texttt{wlo1} wireless interface, the following iptables rules are applied:
@ -107,7 +109,6 @@ Access the container's shell:
incus exec deb1 -- su - user
\end{lstlisting}
% New section for veth pair setup
\section{Setting Up a Veth Pair Between Container and Network Namespace}
To enable direct communication between a container and a network namespace, a virtual Ethernet (\texttt{veth}) pair is created. The following Python script (\texttt{link.py}) is used to create a \texttt{veth} pair between the \texttt{deb1} (an Incus container) and the \texttt{ns1} network namespace, with interfaces named \texttt{vA} and \texttt{vB}.
@ -116,10 +117,12 @@ sudo python3 link.py -n1 vA -t2 incus -ns2 deb1 -n2 vB
\end{lstlisting}
This command:
\begin{itemize}
\item Creates a \texttt{veth} pair with one end (\texttt{vA}) in the default namespace and the other end (\texttt{vB}) in the \texttt{deb1}'s network namespace.
\item Ensures the interfaces are set up and operational, allowing network traffic to flow between the container and the \texttt{ns1} namespace (or default namespace if \texttt{ns1} is not explicitly created).
\end{itemize}
- Creates a \texttt{veth} pair with one end (\texttt{vA}) in the default namespace and the other end (\texttt{vB}) in the \texttt{deb1}'s network namespace.
- Ensures the interfaces are set up and operational, allowing network traffic to flow between the container and the \texttt{ns1} namespace (or default namespace if \texttt{ns1} is not explicitly created).
The script uses the \texttt{pyroute2} library to manage network interfaces and namespaces, and supports container types such as Incus, LXC, LXD, and Docker. Ensure the \texttt{deb1} is running in Incus before executing the command.
@ -148,7 +151,6 @@ Apply the configuration:
incus exec deb1 -- netplan apply
\end{lstlisting}
\subsection{Installing dnsmasq}
Update the package list and install \texttt{dnsmasq}:
\begin{lstlisting}[language=bash]
@ -156,7 +158,6 @@ incus exec deb1 -- apt update
incus exec deb1 -- apt install dnsmasq -y
\end{lstlisting}
\subsection{Configuring dnsmasq}
Edit the \texttt{dnsmasq} configuration file at \texttt{/etc/dnsmasq.conf}:
\begin{lstlisting}[language=bash]
@ -180,15 +181,45 @@ dhcp-option=6,8.8.8.8,8.8.4.4
\end{lstlisting}
\textbf{Explanation:}
\begin{itemize}
\item \texttt{domain-needed}: Prevents incomplete domain names from being sent to upstream DNS.
\item \texttt{bogus-priv}: Blocks reverse DNS lookups for private IP ranges.
\item \texttt{no-resolv}: Disables reading \texttt{/etc/resolv.conf}.
\item \texttt{server}: Specifies upstream DNS servers (Google DNS in this case).
\item \texttt{local} and \texttt{domain}: Configures a local domain.
\item \texttt{dhcp-range}: Defines the IP range for DHCP clients (from 192.168.1.100 to 192.168.1.200, lease time 12 hours).
\item \texttt{dhcp-option}: Sets the default gateway (option 3) and DNS servers (option 6).
\end{itemize}
- \texttt{domain-needed}: Prevents incomplete domain names from being sent to upstream DNS.
- \texttt{bogus-priv}: Blocks reverse DNS lookups for private IP ranges.
- \texttt{no-resolv}: Disables reading \texttt{/etc/resolv.conf}.
- \texttt{server}: Specifies upstream DNS servers (Google DNS in this case).
- \texttt{local} and \texttt{domain}: Configures a local domain.
- \texttt{dhcp-range}: Defines the IP range for DHCP clients (from 192.168.1.100 to 192.168.1.200, lease time 12 hours).
- \texttt{dhcp-option}: Sets the default gateway (option 3) and DNS servers (option 6).
% ————————————————————————————————
% 🔧 NOWA SEKCJA: System-Level Adjustments
% ————————————————————————————————
\subsection{System-Level Adjustments for Network Stability}
In some cases, especially in nested or privileged containers, additional system-level adjustments are necessary to ensure proper network functionality and avoid conflicts.
To remount the \texttt{/sys} filesystem as read-write (required if certain networking tools fail due to mount restrictions):
\begin{lstlisting}[language=bash]
sudo mount -o remount,rw /sys
sudo systemctl restart systemd-udevd
\end{lstlisting}
Additionally, to prevent DNS conflicts with \texttt{systemd-resolved}, which may interfere with \texttt{dnsmasq}, stop and disable the service:
\begin{lstlisting}[language=bash]
sudo systemctl stop systemd-resolved
sudo systemctl disable systemd-resolved
\end{lstlisting}
This ensures that \texttt{dnsmasq} can bind to port 53 without conflicts. If you require \texttt{systemd-resolved}, consider configuring it to listen on a different interface or using socket activation.
% ————————————————————————————————
\subsection{Starting and Enabling dnsmasq}
Restart and enable the \texttt{dnsmasq} service:
@ -210,14 +241,16 @@ To test DHCP, connect a client device to the same network and verify that it rec
\section{Troubleshooting}
If \texttt{dnsmasq} fails to start:
\begin{itemize}
\item Check the logs: \texttt{incus exec deb1 -- journalctl -u dnsmasq}.
\item Ensure no other service is using port 53 (DNS) or 67 (DHCP).
\item Verify the network configuration with \texttt{incus exec deb1 -- ip a} and \texttt{incus exec deb1 -- ping 8.8.8.8}.
\end{itemize}
- Check the logs: \texttt{incus exec deb1 -- journalctl -u dnsmasq}.
- Ensure no other service is using port 53 (DNS) or 67 (DHCP).
- Verify the network configuration with \texttt{incus exec deb1 -- ip a} and \texttt{incus exec deb1 -- ping 8.8.8.8}.
\section{Conclusion}
This guide configures \texttt{dnsmasq} as a DNS and DHCP server in an Incus container on Debian. The Netplan configuration ensures proper network setup. For advanced configurations, refer to the \texttt{dnsmasq} documentation (\texttt{man dnsmasq}).
\end{document}