currently I'm trying to setup a three node mysql-innodb-cluster on a maas-deployment using juju.
The setup process worked flawlessly and the deployment of other charms worked fine. When deploying the cluster I would like to achieve that in separate lxd-container. But that doesn't work. I get the error:
Did I miss some critical configuration step here?
did you turn OFF ipv6? that is generally needed when setting up LXD & Juju.. you do that in the lxd init prompts
if you can, you need to wipe all the machine or at the least your network bridges for LXD
Related
I have a hybrid GKE Cluster running with some Linux and Windows nodes. I followed this how-to (https://cloud.google.com/kubernetes-engine/docs/how-to/ip-masquerade-agent) in order to configure the masquerade for some of my networks and it works like a charm on Linux Nodes. But it doesn't work on the windows hosts, it gives me this error:
Failed to create pod sandbox: rpc error: code = Unknown desc = failed to start sandbox container for pod "ip-masq-agent-pc9vn": Error response from daemon: network host not found
Anyone knows how can I configure masquerade on Windows Nodes?
Adding details:
I know that Linux containers don't run on Windows nodes, so ip-masq-agent won't run on that node and I know that I can use taints or labels to avoid the pods to be scheduled on that node.
I use Windows nodes with kubernetes because I have some .Net Framework applications running on it, and it works fine. My problem is that I need to masquerade the connections from the pod to hosts outside of the cluster because the source connections are the Pod IPs, not the node IP.
On Linux machines, I can do that using ip-masq-agent, that mange Iptables rules to masquerade the traffic. But on Windows, the ip-masq-agent doesn't work, for the reasons that #Rico said in his answer.
I want to know if someone knows another way to achieve the same thing on Windows nodes.
I can use a "NAT Machine" holding all connections in the middle and route all traffic to that machine, but it's a really ugly way to do that.
Solution:
I end up allowing the pod network to go through VPN. Thank you for all the replies.
The simple answer is you can't. iptables is a Linux thing. Windows has some alternatives that you can use to set up NAT (netsh) like described here: https://superuser.com/questions/1088309/windows-10-nat-port-forwarding-ip-masquerade, but there's no specific K8s support so you will be on your own.
To make sure your ip-masq-agent doesn't get scheduled on your Windows nodes you can follow a NodeSelector, Taint/Toleration approach as described here.
A wider question would be what are you trying to run on the Windows machines? Windows containers are not interchangeable with Linux containers. If you want your Linux pods and Windows pods to talk to each other have you tried Flannel?
I'm used to connect to my cluster using telepresence and access cluster services locally.
Now, I need to make services in the cluster available to a group of applications that are running in docker containers locally. We can say that it's the inverse use case.
I've an app that is running in a docker container. It access services that are deploy using docker-compose. It has been done by using a network:
docker network create myNetwork
// Make app 1 to use it
docker network connect myNetwork app1
// App 2 uses docker compose, so myNetwork is defined in it and here I just:
docker-compose up
My app1 access correctly the containers/services running in app2. However, I still need it to access a service from my cluster!
I've tried make a tunnel from my host to the cluster with telepresence and then try to access the service as if it were in my host. However it seems not to work. If I go into my app1 container and do a curl to see if the service name resolves:
curl: (6) Could not resolve host: my_cluster_service_name
Is my approach wrong? Am I missing an operation or consideration? How could I accomplish it?
Docker version: Docker version 19.03.8 for Mac
I've find a way to solve the problem.
Instead of trying to use telepresence as for the inverse use case, solution comes by using a port-forward with k9s. When creating it, it's important to do not leave the default interface, that is set to localhost, and put 0.0.0.0 instead to ensure that it listens traffic from all interfaces.
Then I've changed my containers from inside, making the services to point to my host's IP when trying to resolve the service names. Use the method that better fits your case for this: since it's not a production environment I just tried hardcoding my host IP manually to check if the connectivity was achieved.
To point to an specific service of your cluster you need to use different ports since they will be all mapped to your host with different port-forwards. Name resolving is no longer needed.
With this configuration, your container request will reach your host, where the port-forward routes it to the cluster. Connectivity is OK with this setup and the problem is solved.
I tried to find the answer in previous post, but i did not find it !
My question seems dumb, i'm just trying to figure it out :)
I'm new to docker and kubernetes, i'm trying to understand the architecture of kubernetes cluster, nodes, and pods.
I'm using two machines with docker installed, each machine have two containers running, i want to install MicroK8s to start playing with kubernetes, my questions are :
As below image > Can I install it on separate machine and connect it to my docker host machines so it will manage my containers their with support of some sort of (agent/ maybe services) ?, Or kubernetes/MicroK8s must be installed on the machine that will host the containers ?
Can i add my running docker containers directly to a pod ? or i must re-create them ?
Many thanks
You can play with any VM software(cpu virtualization required).
You can set up 3 VMs(master, node1,node2). You have to install kubernetes in each VM. When you connect them thru calico they communicate each other. When you make pods with app or db , you can loadbalance to node1 and node2 or more from master. Then you can create a service to export route to the pods. Or If you want to run everything in one big server, you can. Horizontal scaling or vertical scaling is your choice.
you cant mount a running docker container to the pod but you can load a docker image from any registry.
I'm currently experimenting with Swarm Services with Docker for Windows. The new Win10 Insider build supports overlay networking for Windows containers and I was pleased to see my IIS service actually starting. The only issue i came across is that i can not reach the service in the browser, despite trying multiple things such as different ports and networks. The command issued is as following:
docker service create --name webfarm -p 80:80 microsoft/iis
I have also tried to use the --network flag to try different networks and I have made sure to test all IP addresses visible in the docker service inspect webfarm command.
docker service ps webfarm does indicate that my service is in state RUNNING and does not have any errors, so i don't know what else i can try. Especially since these commands worked fine on Linux with Apache.
I was wondering if anyone has been able to successfully create a service using Windows Containers on the Windows Insider build (15046), and if so, how?
Never mind, i found this actually is not supported yet.
The following source states:
"At the moment only DNS round robin is implemented as described in the Microsoft blog post. You cannot use to publish ports externally right now. More to come in the near future." (https://stefanscherer.github.io/docker-swarm-mode-windows10/)
And indeed, the blogposts states the following:
"Currently, Windows supports DNS Round-Robin load balancing between services. The routing mesh for Windows Docker hosts is not yet supported, but will be coming soon. Users seeking an alternative load balancing strategy today can setup an external load balancer (e.g. NGINX) and use Swarm’s publish-port mode to expose container host ports over which to load balance." (https://blogs.technet.microsoft.com/virtualization/2017/02/09/overlay-network-driver-with-support-for-docker-swarm-mode-now-available-to-windows-insiders-on-windows-10/)
I guess I'll have to wait for this feature, in the meantime I will use the alternative.
I am running Windows 7 on my desktop at work and I am signed in to a regular user account on the VPN. To develop software, we are to normally open a Dev VM and work from in there however recently I've been assigned a task to research Docker and Mongo DB. I have very limited access to what I can install on the main machine.
Here lies my problem:
Is it possible for me to connect to a MongoDB instance inside a container inside the docker machine from Windows and make changes? I would ideally like to use a GUI tool such as Mongo Management Studio to make changes to a Mongo database within a container.
By inspecting the Mongo container, it has the ports listed as: 0.0.0.0:32768 -> 27017/tcp
and docker-machine ip (vm name) returns 192.168.99.111.
I have commented out the 127.0.0.1 binding host ip within the mongod.conf file also.
From what I have researched so far, most users resolve their problem by connecting to their docker-machine IP with the port they've set with -p or been given with -P. Unfortunately for me, trying to connect with 192.168.99.111:32768 does not work.
I am pretty stumped and quite new to this environment. I am able to get inside the container with bash and manipulate the database there however I'm wondering if I can do this within Windows.
Thank you if anyone can help.
After reading Smutje's advice to ping the VM IP and testing it out to no avail, I attempted to find a pingable IP which would hopefully move me closer to my goal.
By doing "ifconfig" within the Boot2Docker VM (but not inside the container), I was able to locate another IP listed under eth0. This IP looks something like 134.36.xxx.xxx to me and is pingable. With the Mongo container running I can now access the database from within Mongo Management Studio by connecting to 134.36.xxx.xxx:32768 and manipulate the data from there.
If you have the option of choosing the operating system for your dev VM, go with Ubuntu and setup docker with all of the the containers you want to test on that. Either way, you will need to have a VM for testing docker on windows since it uses VirtualBox if i'm not mistaken. Instead, setup an Ubuntu VM and do all of your testing on that.