nsenter | It is a small tool allowing to enter into namespaces | Script Programming library

by jpetazzo Shell Version: Current License: Apache-2.0

X-Ray Key Features Code Snippets Community Discussions(10)Vulnerabilities Install Support

kandi X-RAY | nsenter Summary

nsenter is a Shell library typically used in Programming Style, Script Programming applications. nsenter has no bugs, it has no vulnerabilities, it has a Permissive License and it has medium support. You can download it from GitHub.

It is a small tool allowing to enter into namespaces. Technically, it can enter existing namespaces, or spawn a process into a new set of namespaces. "What are those namespaces you're blabbering about?" We are talking about container namespaces. nsenter can do many useful things, but the main reason why I'm so excited about it is because it lets you enter into a Docker container.

Support

Quality

Security

License

Reuse

Support

nsenter has a medium active ecosystem.

It has 2571 star(s) with 279 fork(s). There are 89 watchers for this library.

It had no major release in the last 6 months.

nsenter has no issues reported. There are no pull requests.

It has a neutral sentiment in the developer community.

The latest version of nsenter is current.

Quality

nsenter has 0 bugs and 0 code smells.

Security

nsenter has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.

nsenter code analysis shows 0 unresolved vulnerabilities.

There are 0 security hotspots that need review.

License

nsenter is licensed under the Apache-2.0 License. This license is Permissive.

Permissive licenses have the least restrictions, and you can use them in most projects.

Reuse

nsenter releases are not available. You will need to build from source code and install.

Installation instructions, examples and code snippets are available.

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nsenter Key Features

No Key Features are available at this moment for nsenter.

nsenter Examples and Code Snippets

No Code Snippets are available at this moment for nsenter.

Community Discussions

Trending Discussions on nsenter

Calling one docker from another docker encountered connection refused

Why do commands listed in the .sh script are not executed while manual typing works?

Kubelet service is not running. It seems like the kubelet isn't running or healthy

How do I connect and manage Kubernetes cluster from POD using nsenter utility

kubelet won't start after kuberntes/manifest update

How to connect host machine from container using nsenter utility

How does Go write code and execute system commands to start a new terminal as a result?

Is there a way to configure Docker's embedded DNS server's upstream nameserver's port?

concourse start container failed: getting the final child's pid from pipe caused: EOF

How to auto run commands when log on to Windows Subsystem for Linux

QUESTION

Calling one docker from another docker encountered connection refused

Asked 2022-Feb-28 at 11:10

I am using kubernetes (by windows 10 - docker desktop).

I am using mysql, that is running by helm 3 (loaded from bitnami repository).

I am creating another application. For now, I am testing on docker (not in kubernetes yet).

Everything is fine, but when trying to connect the database from my project (BTW - Project works fine, but not when running on docker).

Something like:

...

ANSWER

Answered 2022-Feb-28 at 11:10

Docker containers are isolated from other containers and the external network by default. There are several options to establish connection between Docker containers:

Docker sets up a default bridge network automatically, through which the communication is possible between containers and between containers and the host machine. Both your containers should be on the bridge network - for container with your project to connect to your DB container by referring to it's name. More details on this approach and how it can be set up is here.
You can also create user-defined bridge network - basically, your own custom bridge network - and attach your Docker containers to it. In this way, both containers won't be connected to the default bridge network at all. Example of this approach is described in details here.
1. First, user-defined network should be created:

Source https://stackoverflow.com/questions/71207253

QUESTION

Why do commands listed in the .sh script are not executed while manual typing works?

Asked 2022-Jan-08 at 22:39

I have the OCI runtime bundle which I run with Dobby - RDK utility (use crun under the hood). I have specified my custom entrypoint.sh script to be run on startup in config.json:

...

ANSWER

Answered 2021-Dec-26 at 02:01

Try substitute lighttpd in your script with the full path to it, i.e. what prints when you run which lighttpd. For example, if which lighttpd prints /usr/sbin/lighttpd, your script should be like this:

Source https://stackoverflow.com/questions/70483670

QUESTION

Kubelet service is not running. It seems like the kubelet isn't running or healthy

Asked 2021-Dec-05 at 08:04

I have configured 1 master 2 workers. after installation successfully kubernetes. It is OK with worker1 joining cluster but I can not join worker2 to the cluster because kubelet service is not running. It seems like the kubelet isn't running or healthy

sudo kubectl get nodes:

NAME STATUS ROLES AGE VERSION
master1 Ready control-plane,master 23m v1.22.2
node1 NotReady 4m13s v1.22.2

I want to know why the kubelet service is not running.

Here kubelet logs.

...

ANSWER

Answered 2021-Dec-05 at 08:04

First, check if swap is diabled on your node as you MUST disable swap in order for the kubelet to work properly.

Source https://stackoverflow.com/questions/70229371

QUESTION

How do I connect and manage Kubernetes cluster from POD using nsenter utility

Asked 2021-Nov-25 at 14:58

I am using multi node Kubernetes cluster. I am using following YAML to connect and manage host machine.

...

ANSWER

Answered 2021-Nov-25 at 14:58

Short answer: You can connect from the pod using nsenter utility to the only one node - the node that pod is hosted on, but better don't do that because deploying pods with wide permissions is against best security practices.

You can't connect to the other nodes, as pod is hosted on only one node. Setting host... fields means that they are only sharing resources with the host - one host node and simply it's not possible to achieve it using nsenter utility.

This diagram is good representation of the Kuberentes architecture related to pods and nodes:

For connecting to the host node just run following command:

Source https://stackoverflow.com/questions/69998723

QUESTION

kubelet won't start after kuberntes/manifest update

Asked 2021-Nov-16 at 10:01

This is sort of strange behavior in our K8 cluster.

When we try to deploy a new version of our applications we get:

...

ANSWER

Answered 2021-Nov-15 at 17:56

Posting comment as the community wiki answer for better visibility

This issue was due to kubelet certificate expired and fixed following these steps. If someone faces this issue, make sure /var/lib/kubelet/pki/kubelet-client-current.pem certificate and key values are base64 encoded when placing on /etc/kubernetes/kubelet.conf

Source https://stackoverflow.com/questions/69923716

QUESTION

How to connect host machine from container using nsenter utility

Asked 2021-Nov-09 at 16:13

There is a utility called nsenter in ubuntu. nsenter is a small tool allowing to enter into namespaces. It will enter into your docker container. I want to control the host machine from the docker container. How do I connect the host machine from the container using the nsenter utility?

...

ANSWER

Answered 2021-Nov-09 at 16:13

nsenter allows you to join the Linux namespaces of a targeted process id (PID).

First, run a container that shares your hosts PID namespace with --pid=host. The container has to be privileged with --privileged, otherwise executing nsenter will fail with an "Operation not permitted" error. The container is kept running indefinitely by executing tail -f /dev/null.

Source https://stackoverflow.com/questions/69893706

QUESTION

How does Go write code and execute system commands to start a new terminal as a result?

Asked 2021-Aug-14 at 18:07

When I execute an ordinary command in Go code, for example ls -ls, it can be executed normally and return the result:

...

ANSWER

Answered 2021-Aug-14 at 18:07

You've got a couple of problems there.

First, you're trying to spawn an interactive command (nsenter will by default start a shell in the target namespace), but you're also connecting stdout to a variable, which means even if it works you wouldn't be able to see any output until after the command exits, which is probably not what you want.

Secondly, you're not connecting stdin to anything useful, which means that most interactive commands will simply exit.

To start an interactive subcommand in Go, you would write something like this:

Source https://stackoverflow.com/questions/68784613

QUESTION

Is there a way to configure Docker's embedded DNS server's upstream nameserver's port?

Asked 2021-Apr-27 at 01:18

General context

Docker daemon comes with an embedded DNS server. It resolves local Docker swarm and network records and forwards queries for external records to an upstream nameserver configured with --dns 1.

Docs say you can set an IP address for this upstream nameserver with --dns=[IP_ADDRESS...]. The default port used is 53.

My question

Can I configure the port used as well?

My host's /etc/docker/daemon.json shows "dns": ["10.99.0.1"],. Is there a way for me to specify something like "dns": ["10.99.0.1:53"], so that dockerd always knows to forward DNS queries to port 53?

My use case

In my case, 10.99.0.1 is the IP of a localhost bridge interface. I run a local DNS caching server on this host. So DNS queries sent to 10.99.0.1:53 work. But dockerd forwards queries originating from containers connected to user-defined bridge networks (created with docker network create) to non-standard ports it picks. See terminal output below.

Detailed terminal output and debugging info

"toogle" is a Docker container connected to a Docker network I created with docker network create. 127.0.0.11 is another loopback address. DNS queries originating from within Docker containers connected to user-defined Docker networks are destined for this IP.

Is Docker's embedded DNS server actually running?

DNS queries are routed by toogle's firewall rules this way.

...

ANSWER

Answered 2021-Apr-27 at 01:18

I don't think there's a way to do this. I also misread the output. Docker daemon was forwarding to port 53.

read udp 172.20.0.127:37928->10.99.0.1:53: i/o timeout

Source https://stackoverflow.com/questions/67221167

QUESTION

concourse start container failed: getting the final child's pid from pipe caused: EOF

Asked 2020-Oct-19 at 08:32

Env:amazon linux2
kernel version: 4.14.198-152.320.amzn2.x86_64
concourse version:v6.6.0
Issue:

After I setup concourse on amazon EC2, I can login concourse web and create pipeline. But when I trigger the pipeline build, I got below error message: runc run: exit status 1: container_linux.go:367: starting container process caused: process_linux.go:338: getting the final child's pid from pipe caused: EOF

Checking the backend log:

{"timestamp":"2020-10-15T03:14:44.622775204Z","level":"info","source":"guardian","message":"guardian.create.containerizer-create.create.completing","data":{"bundle":"/home/concourse/worker/depot/2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","handle":"2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","session":"99.3.2"}} {"timestamp":"2020-10-15T03:14:44.624243772Z","level":"debug","source":"guardian","message":"guardian.create.containerizer-create.create.runc","data":{"bundle":"/home/concourse/worker/depot/2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","handle":"2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","message":"nsexec:601 nsexec started","session":"99.3.2"}} {"timestamp":"2020-10-15T03:14:44.624281598Z","level":"debug","source":"guardian","message":"guardian.create.containerizer-create.create.runc","data":{"bundle":"/home/concourse/worker/depot/2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","handle":"2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","message":"try_mapping_tool:240 nsenter: mapping tool not present: Operation not permitted","session":"99.3.2"}} {"timestamp":"2020-10-15T03:14:44.624308669Z","level":"debug","source":"guardian","message":"guardian.create.containerizer-create.create.runc","data":{"bundle":"/home/concourse/worker/depot/2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","handle":"2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","message":"nsexec:889 nsenter: failed to sync with parent: read(SYNC_USERMAP_ACK): Invalid argument","session":"99.3.2"}} {"timestamp":"2020-10-15T03:14:44.624328533Z","level":"debug","source":"guardian","message":"guardian.create.containerizer-create.create.runc","data":{"bundle":"/home/concourse/worker/depot/2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","handle":"2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","message":"log pipe has been closed: EOF","session":"99.3.2"}} {"timestamp":"2020-10-15T03:14:44.624349468Z","level":"debug","source":"guardian","message":"guardian.create.containerizer-create.create.runc","data":{"bundle":"/home/concourse/worker/depot/2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","handle":"2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","message":"container_linux.go:367: starting container process caused: process_linux.go:338: getting the final child's pid from pipe caused: EOF","session":"99.3.2"}} {"timestamp":"2020-10-15T03:14:44.624379918Z","level":"info","source":"guardian","message":"guardian.create.containerizer-create.create.finished","data":{"bundle":"/home/concourse/worker/depot/2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","handle":"2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","session":"99.3.2"}} {"timestamp":"2020-10-15T03:14:44.624412285Z","level":"error","source":"guardian","message":"guardian.create.containerizer-create.runtime-create-failed","data":{"error":"runc run: exit status 1: container_linux.go:367: starting container process caused: process_linux.go:338: getting the final child's pid from pipe caused: EOF","handle":"2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","session":"99.3"}} {"timestamp":"2020-10-15T03:14:44.624429680Z","level":"info","source":"guardian","message":"guardian.create.containerizer-create.finished","data":{"handle":"2b4ce51a-c28d-4aac-7122-b82cd1cbb99e","session":"99.3"}}

I already highlight the message which may cause this issue. Thank you to help me to find the root cause.

...

ANSWER

Answered 2020-Oct-19 at 08:32

I found the root cause is system missing some tools. I replace it using a new system image, then working fine.

Source https://stackoverflow.com/questions/64364438

QUESTION

How to auto run commands when log on to Windows Subsystem for Linux

Asked 2020-Sep-02 at 07:14

I have a Ubuntu 20.04 running within WSL 2 on a Windows 10 computer.

Every time I login to Ubuntu, I had to manually execute these four line by pasting it one by one in the Windows 10 Terminal.

...

ANSWER

Answered 2020-Sep-02 at 07:14

You can use .bashrc file to execute commands whenever you open the terminal. It should be located at $HOME directory.

Source https://stackoverflow.com/questions/63687253

Community Discussions, Code Snippets contain sources that include Stack Exchange Network

Vulnerabilities

No vulnerabilities reported

Install nsenter

This is because my preferred distros (Debian and Ubuntu) ship with an outdated version of util-linux (the package that should contain nsenter). Therefore, if you need nsenter on those distros, you have to juggle with APT repository, or compile from source, or… Ain't nobody got time for that. I'm going to make a very bold assumption: if you landed here, it's because you want to enter a Docker container. Therefore, you won't mind if my method to build nsenter uses Docker itself.
You can also install nsenter to another folder. In that case, you will need to specify the full path of nsenter to run it.

Support

For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .

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