Kubernetes RBAC can be used to give permissions to a subject in a particular Namespace. Can the same be accomplished with Cloud IAM?
Not at the moment, no. IAM is used to assign and verify permissions when interacting with GCP APIs. IAM can only provide access to the GKE API, which does not take into account namespaces.
As you mentioned, RBAC is your option for more granular permissions within the cluster
If I got your point correctly that:
The IAM roles for a GKE kubernetes cluster are very simple, "Admin, Read/Write, Read".
But you need more fine-grained control over the kubernetes cluster.
In this case:
There's a new "Alpha" feature in Google Cloud's IAM which wasn't available previously.
Under IAM > Roles
You can now create custom IAM roles with your own subset of permissions.
You can create a minimal role which allows for example gcloud container clusters get-credentials to work, but nothing else, allowing permissions within the kubernetes cluster to be fully managed by RBAC.
It will allow you to get more fine-grained access configurations for kubernetes cluster.
Related
I'm using a juicefs-csi in GKE. I use postgre as meta-store and GCS as storage. The corresponding setting is as follow:
node:
# ...
storageClasses:
- name: juicefs-sc
enabled: true
reclaimPolicy: Retain
backend:
name: juicefs
metaurl: postgres://user:password#my-ec2-where-postgre-installed.ap-southeast-1.compute.amazonaws.com:5432/the-database?sslmode=disable
storage: gs
bucket: gs://my-bucket
# ...
According to this documentation, I don't have to specify access key/secret (like in S3).
But unfortunately, whenever I try to write anything to the mounted volume (with juicefs-sc storage class), I always get this error:
AccessDeniedException: 403 Caller does not have storage.objects.create access to the Google Cloud Storage object.
I believe it should be related to IAM role.
My question is, how could I know which IAM user/service account is used by juicefs to access GCS, so that I can assign a sufficient role to it?
Thanks in advance.
EDIT
Step by step:
Download juicefs-csi helm chart
Add values as described in the question, apply
Create a pod that mount from PV with juicefs-sc storage class
Try to read/write file to the mount point
Ok I misunderstood you at the beginning.
When you are creating GKE cluster you can specify which GCP Service Account will be used by this cluster, like below:
By Default it's Compute Engine default service account (71025XXXXXX-compute#developer.gserviceaccount.com) which is lack of a few Cloud Product permissions (like Cloud Storage, it has Read Only). It's even described in this message.
If you want to check which Service Account was set by default to VM, you could do this via
Compute Engine > VM Instances > Choose one of the VMs from this cluster > In details find API and identity management
So You have like 3 options to solve this issue:
1. During Cluster creation
In Node Pools > Security, you have Access scopes where you can add some additional permissions.
Allow full access to all Cloud APIs to allow access for all listed Cloud APIs
Set access for each API
In your case you could just use Set access for each API and change Storage to Full.
2. Set permissions with a Service Account
You would need to create a new Service Account and provide proper permissions for Compute Engine and Storage. More details about how to create SA you can find in Creating and managing service accounts.
3. Use Workload Identity
Workload Identity on your Google Kubernetes Engine (GKE) clusters. Workload Identity allows workloads in your GKE clusters to impersonate Identity and Access Management (IAM) service accounts to access Google Cloud services.
For more details you should check Using Workload Identity.
Useful links
Configuring Velero - Velero is software for backup and restore, however steps 2 and 3 are mentioned there. You would just need to adjust commands/permissions to your scenario.
Authenticating to Google Cloud with service accounts
We can check the service accounts in Kubernetes Cluster. Likewise, Is it possible to check the existing users and groups of my Kubernetes cluster with Cluster Admin privileges. If yes then how ? If no then why ?
NOTE: I am using EKS
Posting this as a community wiki, feel free to edit and expand.
This won't answer everything, however there are some concepts and ideas.
In short words there's no easy way. It's not possible to do using kubernetes itself. Reason for this is:
All Kubernetes clusters have two categories of users: service accounts
managed by Kubernetes, and normal users.
It is assumed that a cluster-independent service manages normal users
in the following ways:
an administrator distributing private keys
a user store like Keystone or Google Accounts
a file with a list of usernames and passwords
In this regard, Kubernetes does not have objects which represent normal
user accounts. Normal users cannot be added to a cluster through an
API call.
Source
More details and examples from another answer on SO
As for EKS part which is mentioned, it should be done using AWS IAM in connection to kubernetes RBAC. Below articles about setting up IAM roles in kubernetes cluster. Same way it will be possible to find which role has cluster admin permissions:
Managing users or IAM roles for your cluster
provide access to other IAM users and roles
If another tool is used for identity managing, it should be used (e.g. LDAP)
I recently built an EKS cluster w/ Terraform. In doing that, I Created 3 different roles on the cluster, all mapped to the same AWS IAM Role (the one used to create the cluster)
Now, when I try to manage the cluster, RBAC seems to use the least privileged of these (which I made a view role) that only has read-only access.
Is there anyway to tell config to use the admin role instead of view?
I'm afraid I've hosed this cluster and may need to rebuild it.
Some into
You don't need to create a mapping in K8s for an IAM entity that created an EKS cluster, because by default it will be mapped to "system:masters" K8s group automatically. So, if you want to give additional permissions in a K8s cluster, just map other IAM roles/users.
In EKS, IAM entities are used authentication and K8s RBAC are for authorization purposes. The mapping between them is set in aws-auth configMap in kube-system namespace,
Back to the question
I'm not sure, why K8s may have mapped that IAM user to the least privileged K8s user - it may be the default behaviour (bug?) or due to the mapping record (for view perms) being later in the CM, so it just re-wrote the previous mapping.
Any way, there is no possibility to specify a K8s user to use with such mapping.
Also, if you used eksctl to spin up the cluster, you may try creating a new mapping as per docs, but not sure if that will work.
Some reading reference: #1, #2
I'm developing a service running in Google Kubernetes Engine and I would like to use Google Cloud functionality from that service.
I have created a service account in Google Cloud with all the necessary roles and I would like to use these roles from the pod running my service.
I have read this: https://cloud.google.com/kubernetes-engine/docs/tutorials/authenticating-to-cloud-platform
and I was wondering if there is an easier way to "connect" the two kinds of service accounts ( defined in Kubernetes - defined in Google Cloud IAM ) ?
Thanks
I don't think there is any direct link. K8s service accounts are purely internal. You could try granting GIAM permissions to serviceaccount:name but that seems unlikely to work. More likely you would put the Google SA credentials in a secret and then write an RBAC policy giving your K8s SA read access to it.
Read the topic which I have shared. You need to enable Workload Identity on your cluster and then you can annotate Kubernetes service account with IAM on google.
gke-document
I created a kubernetes cluster under my user account on IBM Bluemix, and added another into my organization. But he can't see my cluster. Is there any other configure?
To manage cluster access, see this link from the IBM Bluemix Container Service documentation. Summarised here:
Managing cluster access
You can grant access to your cluster to other users, so that they can
access the cluster, manage the cluster, and deploy apps to the
cluster.
Every user that works with IBM Bluemix Container Service must be
assigned a service-specific user role in Identity and Access
Management that determines what actions this user can perform.
Identity and Access Management differentiates between the following
access permissions.
IBM Bluemix Container Service access policies
Access policies determine the cluster management actions that you can
perform on a cluster, such as creating or removing clusters, and
adding or removing extra worker nodes.
Cloud Foundry roles
Every user must be assigned a Cloud Foundry user role. This role
determines the actions that the user can perform on the Bluemix
account, such as inviting other users, or viewing the quota usage. To
review the permissions of each role, see Cloud Foundry roles.
RBAC roles
Every user who is assigned an IBM Bluemix Container Service access
policy is automatically assigned an RBAC role. RBAC roles determine
the actions that you can perform on Kubernetes resources inside the
cluster. RBAC roles are set up for the default namespace only. The
cluster administrator can add RBAC roles for other namespaces in the
cluster. See Using RBAC Authorization in the
Kubernetes documentation for more information.