Confusion about kubernetes Networking with external world - mysql

I have a confusion. When i try to access the services like mysql that are externally hosted or outside the cluster, what will be the source address of the packet that are sent to mysql. To make it simple while creating user in mysql for the api to access it, how do i create it?
For example:
CREATE USER 'newuser'#'IP or HOSTNAME' IDENTIFIED BY 'user_password';
What should be the IP? the pod IP or the host IP?
Is there any way through which if the pod is spawn in any node but it can authenticate against mysql?
Thank You

When accessing services outside the kubernetes cluster the source IP will be the regular IP of the node, the application is running on.
So there is no difference if you run the application directly on the node ("metal") or inside a container.
Kubernetes will select an appropriate node to schedule the container (pod) to, so this might change during the lifetime.
If you want to increase the security you should investigate TLS with mutual authentication in addition to the password. The source IP is not the best course of action for dynamic environments like cloud or kubernetes.

Related

How can I port forward in openshift without using oc client . Is there a way we can usejava client to portforward in a pod just like“oc port forward”

I need to access a postgres database from my java code which resides in openshift cluster. I need a way to do so. without initiating port forwarding manually through oc port forward command.
I have tried using openshift java client class openshift connection factory to get the connection by passing server url and username password through which I log in to the console but it dint help.
(This is mostly just a more detailed version of Will Gordon's comment, so credit to him.)
It sounds like you are trying to expose a service (specifically Postgres) outside of your cluster. This is very common.
However the best method to do so does depend a bit on your physical infrastructure because we are by definition trying to integrate with your networking. Look at the docs for Getting Traffic into your Cluster. Routes are probably not what you want, because Postgres is a TCP protocol. But one of the other options in that chapter (Load Balancer, External IP, or NodePort) is probably your best option depending on your networking infrastructure and needs.

Whitelist mysql host from kubernetes

I'm currently trying to build my services on kubernetes using istio and have trouble trying to whitelist all host IPs that are allowed to connect to the Mysql database through mysql.user table.
I always get the following error after a new deployment:
Host 'X.X.X.X' is not allowed to connect to this MySQL server
Knowing that every time i deploy my service a new pod IP always pops out and i have to add replace the old user with the new host IP. I would really like to avoid using '%' for the host.
Is there any way how i could just register the node IP instead to keep its persistence?
Both Kubernetes and Istio provide network-level protections and setting the allowed hosts to "all" is safe.
A Kubernetes network policy is probably the best cluster-level match for what you're looking for. You'd set the database itself to accept connections from all addresses, but then would set a network policy to refuse connections except from pods that have a specific set of labels. Since you control this by label, any new pods that have the appropriate set of labels will be automatically granted access without manual changes.
Depending on your needs, the default protection given by a ClusterIP service may be enough for you. If a service is ClusterIP but not any other type, it is unreachable from outside the cluster; there is no network path to make it accessible. This is often enough to prevent casual network snoopers from finding your database.
Istio's authorization system is a little bit more powerful and robust at a network level. It can limit calls by the Kubernetes service account of the caller, and uses TLS certificates rather than just IP addresses to identify the caller. However, it doesn't come enabled by default, and in my limited experience with it it's very easy to accidentally configure it to do things like block Kubernetes health checks or Prometheus metric probes. If you're satisfied with IP-level security this might be more power than you need.

Using SSH tunnel to connect to remote MYSQL database from Node-Red

I have a set of data rolling out of Node-Red that I want to send to a remote MYSQL database. The Node-Red system is running on a Raspberry Pi. How do I make this work? I know how to it using Node.JS but im not sure how to do this in Node-Red. The IP-adress of the Pi is dynamic so simply authorizing its Ip address does not work sadly.
Thanks in advance!
EDIT for clarification:
I want to connect to a remote MYSQL database that is hosted by my webhosting. I have connected a Raspberry Pi to a battery, and I want to save this information in the aforementioned database. Since there will be several battery setups in different locations, I cannot save the data locally. So, one way or another I need to access the remote database through Node-Red. Authorizing one IP-address does't work, since the IP of the Raspberry Pi network is dynamic and thus changes. I think a SSH-Tunnel might be the solution, but I have no idea how to this in Node-Red, and google isnt very helpful.
OK, so as I said in the comments you can make a Username/Password pair for MySQL can be granted permission to any IP address (which is less secure if the username/password is compromised. Set the host to '%' to allow all hosts when setting up the grant options).
To reduce the risk you can restrict the Username/Password to a specific subnet. This could be a wifi network or the subnet associated to the piblic IP (it needs to be the public range as nearly all cellular ISPs use CGNAT) range of the cellular provider you may be using. (See this question for details How to grant remote access to MySQL for a whole subnet?).
If you want to use a SSH tunnel then this will normally be done outside Node-RED with the ssh command line e.g.
ssh -L localhost:3306:localhost:3306 remote.host.com
Then configure the Node-RED MySQL node to point to localhost.
Since the connection will look like it's coming from localhost on the MySQL machine you need make sure the Username/Password is locked down to a that host.
You will probably also want to set up public/private key authentication for the ssh connection.
You may be able to run the ssh command in the node-red-daemon node, which should restart the connection if it gets dropped.

How to connect mysql-client to my spring boot app

I have jar file of springboot and I'm running on compute engineVM
And I also connect SQL-client but what address of mysql should I give in spring boot
I assume you are using GCP's hosted mysql? (Cloud SQL).
If so, then if you are connecting to it via cloud sql proxy, which is running on the same machine, then you just use localhost. The proxy should know the way to the server from there, assuming that you've configured the instance name and project/etc. correctly.
Otherwise, without the proxy, you can use your SQL instance's public IP address, which you can see on the list of running instances when you select the SQL page.
In the second case (using the actual IP address) keep in mind that GCP probably wont let the VM running your application through the firewall to the SQl instance directly. To work around this, you'd have to list your VM's IP address in the Authorized Networks section of the SQL entry (click on your SQL instance in the list and select the Authorization tab). Again, in this case, you need to keep in mind that your VM's IP address is ephemeral by default (unless you made and effort to make it permanent). So if you restart your VM, the above Authorization will no longer make sense. So make sure you make your VM's IP address permanent.

Hadoop cluster on Google Compute Engine: Accessing master node via REST

I have deployed a hadoop cluster on google compute engine. I then run a machine learning algorithm (Cloudera's Oryx) on the master node of the hadoop cluster. The output of this algorithm is accessed via an HTTP REST API. Thus I need to access the output either by a web browser, or via REST commands. However, I cannot resolve the address for the output of the master node which takes the form http://CLUSTER_NAME-m.c.PROJECT_NAME.internal:8091.
I have allowed http traffic and allowed access to ports 80 and 8091 on the network. But I cannot resolve the address given. Note this http address is NOT the IP address of the master node instance.
I have followed along with examples for accessing IP addresses of compute instances. However, I cannot find examples of accessing a single node of a hadoop cluster on GCE, that follows this form http://CLUSTER_NAME-m.c.PROJECT_NAME.internal:8091. Any help would be appreciated. Thank you.
The reason you're seeing this is that the "HOSTNAME.c.PROJECT.internal" name is only resolvable from within the GCE network of that same instance itself; these domain names are not globally visible. So, if you were to SSH into your master node first, and then try to curl http://CLUSTER_NAME-m.c.PROJECT_NAME.internal:8091 then you should successfully retrieve the contents, whereas trying to access from your personal browser will just fail to resolve that hostname into any IP address.
So unfortunately, the quickest way for you to retrieve those contents is indeed to use the external IP address of your GCE instance. If you've already opened port 8091 on the network, simply use gcutil getinstance CLUSTER_NAME-m and look for the entry specifying external IP address; then plug that in as your URL: http://[external ip address]:8091.
If you turned up the cluster using bdutil, a more involved but nicer way to access your cluster is by running the bdutil socksproxy command. This opens a dynamic-port-forwarding SSH tunnel to your master node as a SOCKS5 proxy, so that you can then configure your browser to use localhost:1080 as your proxy server, make sure to enable remote DNS resolution, and then visit your browser using the normal http://CLUSTER_NAME-m.c.PROJECT_NAME.internal:8091 URL.