Creating a Virtual Environment for Python on Ubuntu 16.04

Virtualenv is a tool that creates an isolated environment separate from other projects. In this instance we will be installing different Python versions, including their dependencies.  Creating a virtual environment allows us to work on a Python project without affecting other projects that also use Python. It will utilize Python’s core files on the global environment to run, thus saving you disk space while providing the freedom to use different Python version for separate apps.

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Kubernetes RBAC Authorization

What is RBAC?

Kubernetes Role-Based Access Control or the (RBAC) system describes how we define different permission levels of unique, validated users or groups in a cluster. It uses granular permission sets defined within a .yaml file to allow access to specific resources and operations.

Starting with Kubernetes 1.6, RBAC is enabled by default and users start with no permissions, and as such, permissions must be explicitly granted by an admin to a specific service or resource. These policies are crucial for effectively securing your cluster. They permit us to specify what types of actions are allowed, depending on the user’s role and their function within the organization.

Prerequisites for using Role-Based Access Control

To take advantage of RBAC, you must allow a user the ability to create roles by running the following command:

root@test:~# kubectl create clusterrolebinding cluster-admin-binding \
--clusterrole cluster-admin --user

Afterwards, to start a cluster with RBAC enabled, we would use the flag:

--authorization-mode=RBAC

 

The RBAC Model

Basically, the RBAC model is based on three components; Roles, ClusterRoles and Subjects. All k8s clusters create a default set of ClusterRoles, representing common divisions that users can be placed within.

The “edit” role lets users perform basic actions like deploying pods.
The “view” lets users review specific resources that are non-sensitive.
The “admin” role lets a user manage a namespace.
The “cluster-admin” allows access to administer a cluster.

Roles

A Role consists of rules that define a set of permissions for a resource type. Because there is no default deny rules, a Role can only be used to add access to resources within a single virtual cluster. An example would look something like this:

kind: Role
apiVersion: rbac.authorization.domain.com/home
metadata:
namespace: testdev
name: dev1
rules:
- apiGroups: [""] # "" indicates the core API group
resources: ["pods"] verbs: ["get", "watch", "list"]

In this case, the role defines that a user (dev1) can use the “get”, “watch” or “list” commands for a set of pods in the “testdev” namespace.

ClusterRoles

A ClusterRole can be used to grant the same permissions as a Role but, because they are cluster-scoped, they can also be used to grant wider access to:

  • cluster-scoped resources (like nodes)
  • non-resource endpoints (like a folder named “/test”)
  • namespaced resources (like pods) in and across all namespaces. We would need to run kubectl get pods --all-namespaces

It contains rules that define a set of permissions across resources like nodes or pods.
An example would look something like this:

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
# "namespace" omitted since ClusterRoles are not namespaced
name: secret-reader
rules:
- apiGroups: [""] resources: ["secrets"] verbs: ["get", "watch", "list"]

The default ClusterRole command looks like this:

root@test:~# kubectl create clusterrole [Options]

A command line example to create a ClusterRole named “pod“, that allows a user to perform “get“, “watch” and “list” on a pod would be:

root@test:~# kubectl create clusterrole pod --verb=get,list,watch --resource=pod

 

RoleBinding

A RoleBinding is a set of configuration rules that designate a permission set. It binds a role to subjects (Subjects are simply users, a group of users or service accounts). Those permissions can be set for a single namespace (virtual cluster), with a RoleBinding or, cluster-wide with a ClusterRoleBinding.A RoleBinding is a set of config rules that designate a permission set.

Let’s allow the group “devops1” the ability to modify the resources in the “testdev” namespace:

root@test:~# kubectl create rolebinding devops1 --clusterrole=edit --group=devops1 --namespace=dev rolebinding "devops1" created

Because we used a RoleBinding, these functions only apply within the RoleBinding’s namespace. In this case, a user within the “devops1” group can view resources in the “testdev” namespace but not in a different namespace.

ClusterRoleBindings

A ClusterRoleBinding defines which users have permissions to access which ClusterRoles. Because a “role” contains rules that represent a set of permissions, ClusterRoleBindings extend the defined permissions for:

  • unique namespace in resources like nodes
  • resources in all namespaces in a cluster
  • undefined resource endpoints like ”/foldernames”

The default ClusterRoles (admin, edit, view) can be created using the command:

root@test:~# kubectl create clusterrolebinding [options]

An example of creating a ClusterRoleBinding for user1, user2,and group1 using the cluster-admin ClusterRole

root@test:~# kubectl create clusterrolebinding cluster-admin --clusterrole=cluster-admin --user=user1 --user=user2 --group=group1

 

ConfigMaps

What is a configMap?

A configMap is a resource that easily attaches configuration data to a pod. The information that is stored in a ConfigMap is used to separate config data from other content to keep images/pods portable.

How Do I Create A ConfigMap?

To create a configmap, we simply use the command:
kubectl create configmap <map-name> <data-source>

Let’s create a default.yaml file to create a ConfigMap:
kubectl create -f default.yaml /configmaps/location/basic.yaml

Basic RBAC Commands For Kubectl

Note
These commands will give errors if RBAC isn’t configured correctly.

kubectl get roles
kubectl get rolebindings
kubectl get clusterroles
kubectl get clusterrolebindings
kubectl get clusterrole system:node -o yaml

 

Namespaces

Namespaces are used to define, separate and identify a cluster of resources among a large number of users or spaces. You should only use namespaces when you have a very diverse set of clusters, locations or users. They are used in settings where companies have multiple users or teams that are spread across various projects, locations or departments. A Namespaces also provides a way to prevent naming conflicts across a wide array of clusters.
Inside a Namespace, an object can be identified by a shorter name like ‘cluster1’ or it can be as complex as ‘US.MI.LAN.DC2.S1.R13.K5.ProdCluster1’ but, there can only be a single ‘cluster1’ or a ‘US.MI.LAN.DC2.S1.R13.K5.ProdCluster1’ inside of that namespace. So, the names of resources within a namespace must be unique but, not spanning namespaces. You could have several namespaces which are different, and they can all contain a single ‘cluster1’ object.

You can get a list of namespaces in a cluster by using this command:

root@test:~# kubectl get namespaces
NAME STATUS AGE
cluster2dev Active 1d
cluster2prod Active 4d
cluster3dev Active 2w
cluster3prod Active 4d

Kubernetes always starts with three basic namespaces:

  • default: This is the default namespace for objects that have no specifically identified namespace (eg. the big barrel o’ fun).
  • kube-system: This is the default namespace for objects generated by the Kubernetes system itself.
  • kube-public: This namespace is created automatically and is world readable by everyone. This namespace is primarily reserved for cluster usage, in case that some resources should be visible and readable publicly throughout the whole cluster. The public aspect of this namespace is only a convention, not a requirement.

Finally, the essential concept of role-based access control (RBAC) is to ensure that users who require specific access to a resource can be assigned to those Roles, Clusterroles, and ClusterRolebindings as needed or desired. The granularity of these permission sets is structured and enabled to allow for increased security, ease of security policy modification, simplified security auditing, increased productivity (RBAC cuts down on onboarding time for new employees). Lastly, RBAC allows for increased cost reduction via removing unneeded applications and licensing costs for less used applications. All in all, RBAC is a needed addition to secure your Kubernetes infrastructure.

Ready to Learn More?

Reach out to one of our Solutions team via chat to decide if a Private Cloud service from Liquid Web will meet your Kubernetes needs!

Configure Nginx to Read PHP on Ubuntu 16.04

Nginx is an open source Linux web server that accelerates content while utilizing low resources. Known for its performance and stability Nginx has many other uses such as load balancing, reverse proxy, mail proxy, and HTTP cache. Nginx, by default, does not execute PHP scripts and must be configured to do so.  In this tutorial, we will show you how to enable and test PHP capabilities with your server.

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Remote Desktop Users Group

The most common way to remotely manage a Windows server is through Remote Desktop Protocol. By default, Liquid Web’s Windows servers only allow the members of the administrators’ group remote desktop access. However, the Remote Desktop Users group grants its members access to securely connect to the server through RDP (Remote Desktop Protocol) as well.

This article will go over the basics of the Remote Desktop Users group. By the end, you will be able to add users to the group, understand permissions, and basic user management.

 

Pre-flight

The information below covers methods to configure the Remote Desktop Users group for Windows Server 2012 through Windows Server 2016 on any Liquid Web Windows server. As a valued customer, if you do not feel comfortable performing these steps independently, please contact our support team for additional assistance. Liquid Web support is happy to walk you through the steps and answer any questions you may have.

 

Managing Local Users and Groups

Users and groups on Windows servers are managed in a number of different ways, but the most user-friendly way is through the Local Users and Groups interface. There are several ways to open the interface. However,  the easiest is to run “lusrmgr.msc”. Lusrmgr.msc can be launched by searching the start menu, command line, or through a run dialog. These methods allow you to find users and groups easily.

Note
To manage local users and groups, you will need to be logged in with a user that has the proper permissions to do so. This is most commonly a user that is already a member of the Administrators group.
Within a windows server type in lusrmgr.msc into the search bar to locate Users where you can find existing users and groups.

 

User Management

Once you open the Local Users and Groups interface, you will see two folders on the left, one for Users, and one for Groups. By selecting Users, you will see a full list of local users on the server. You can also see a variety of related tasks by right-clicking Users, Groups, a user’s name, or a blank area of the middle pane.

There are several ways to add a new user through the Local Users and Groups interface. These methods all result in the same “New User” dialog box opening where you can then configure a Username, Password, and other options. Choose one of the options below to create a new user:

  • With the Users folder selected in the left pane, click the Action menu, then select “New User…”.
  • With the Users folder selected in the left pane, click “More Actions” from the right- hand pane, then select “New User…”.
  • Right-click the Users folder, then select “New User…”.
  • With the Users folder selected in the left pane, right-click in a blank area of the middle page, then select “New User…”.

Once you have created a new user, or have identified the username of the existing user, you are ready to assign that user to a Group. Users assigned to a group are known as group members.

 

Group Management

As with user management, group management can also be performed in several ways. The options below cover several of the most common ways to assign a new member to the Remote Desktop Users group:

  • Select the Users folder from the left pane of the Local Users and Groups interface, open the Users Properties window by double-clicking the user, select the “Member Of” tab, then click “Add…”. Now type “Remote Desktop Users” in the text box and click OK.
  • Select the Groups folder from the left pane of the Local Users and Groups interface, double-click the “Remote Desktop Users” group, click “Add…”, enter the user’s name in the text box and click OK.
  • Open the system settings by right-clicking the start menu and selecting “System”, choose “Advanced system settings”, select the “Remote” tab, click the “Select Users…” button then click the “Add” button. Now enter the user’s name in the text box and click OK.
  • Open the “Server Manager”, select “Local Server” from the left pane, click the blue text next to “Computer Name”, select the “Remote” tab, click the “Select Users…” button then click the “Add” button. Now enter the user’s name in the text box and click OK.
    Note
    When selecting users or groups, it is recommended to click the “Check Names” button after typing in the user or group name. If the name is underlined after clicking the “Check Names” button, then the name was identified correctly.

You can also use the “Advanced…” button when selecting users or groups instead of typing its name. Clicking the “Advanced…” button followed by the “Find Now” button will result in a list of users to select.In a windows server, by right-clicking the User folder you can do a variety of tasks like adding a new user.

 

Notes on Permissions & Security

By default, there are no members of the Remote Desktop Users group and only members of the Administrators group are allowed to connect through RDP. Members added to the Remote Desktop Users group are considered non-Administrative users. These users will be unable to perform most management tasks such as installing software, managing IIS, or rebooting the server.

If a user requires management abilities, the user will need explicit access to that task or will need to be a member of the Administrators. Please use the best practice of “least privilege” when configuring your users, groups, and permissions.

 

Test/Verify Group Membership

When configuring new user and group memberships, you should always review group membership once complete.  Reviewing group membership is most commonly performed through the Local Users and Groups interface. In addition to verifying membership, we also recommend attempting a remote desktop connection with your newest Remote Desktop Users group member. If you are unable to connect with your user, please see our Remote Desktop Troubleshooting article.

Once you have logged in with your newest member of the Remote Desktop Users group, you can further verify that groups are set up correctly by running the command “whoami /groups” from a command line. The output of this command lists the username and its associated Group names.

 

Install Rsync and Lsync on CentOS, Fedora or Red Hat

Have you ever needed to copy files from your local computer over to your web server? You may have previously used File Transfer Protocol (FTP) applications for this task, but FTP is prone to being insecure and can be challenging to work with over the command line. What if there was a better way? In this tutorial, we’ll be covering two popular utilities in the Linux world to securely assist in file transfers, rsync and lsyncd. We’ll show you how to install and use both in this article. Let’s dig in!

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Install TeamViewer on Ubuntu 16.04 LTS

VNC (Virtual Network Computing) is a method for sharing a remote desktop environment. Allowing you to remote control another computer or server over the Internet or local network as if you were sitting in front of it. Keyboard and mouse strokes from your computer are relayed to the remote computer/server. There are many different kinds of VNC softwares available today. Several are cross-platform and add additional features, such as chat or file transfers. VNC is often used for remote technical support and remotely accessing files.

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Enabling Let’s Encrypt for AutoSSL on WHM based Servers

With the recent release of cPanel & WHM version 58 there has been the addition of an AutoSSL feature, this tool can be used to automatically provide Domain Validated SSLs for domains on your WHM & cPanel servers.

Initially this feature was released with support provided for only cPanel (powered by Comodo) based SSL certificates, with the plans to support more providers as things progressed. As of now, cPanel & WHM servers running version 58.0.17, and above, can now also use Let’s Encrypt as an SSL provider. More information on Let’s Encrypt can be found here. Continue reading “Enabling Let’s Encrypt for AutoSSL on WHM based Servers”

Transfer an SSL to Ubuntu 16.04 or CentOS 7

SSL certificates have become a de facto part of every website. If you don’t yet have an SSL on your site to encrypt data, you should. Rather than showing an extra layer of security on sites protected by SSL, modern browsers instead now display a warning when a website does not have an SSL, essentially requiring sites to maintain their positive image.

When moving from one server to another, what needs to happen to your SSL to maintain your secure status? We’ll cover the basics for transferring traditional and Let’s Encrypt SSLs to Ubuntu 16.04 and CentOS 7.

Note:
This article will address SSLs in Apache specifically, but the same concepts apply to any service that supports SSL encryption.

Can SSLs be transferred between servers?

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