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How to analyze CloudStack 4.4, many novices are not very clear about this, in order to help you solve this problem, the following editor will explain for you in detail, people with this need can come to learn, I hope you can gain something.

CloudStack 4.4. brief introduction of CloudStack

1. CloudStack is an open source cloud computing platform with high availability and scalability.

2. In fact, CloudStack is more like a commercial product with a very good user interface, each module is well integrated by default, and the process of installation and deployment is relatively easy.

3. Cloudstack supports the management of most mainstream hypervisors, such as KVM,XenServer,VMware,Oracle VM,Xen.

4. CloudStack has the perfect user rights management of commercial software, which allows users to build a secure multi-tenant cloud computing environment. At the same time, it is compatible with Amazon AWS API interface and can be used to manage AWS resources.

5. CloudStack adopts a typical hierarchical structure: client, core engine, and resource layer. It provides different access methods for different types of customers: Web Console, Command Shell and Web Service API. Through them, users can manage and use the underlying computing resources (divided into host, network and storage) to complete functions such as allocating virtual machines on the host, allocating virtual disks and so on.

6. System architecture diagram:

If the virtual machine uses Xen and KVM, CloudStack Agent needs to be installed to support its interaction with the management server. On the other hand, the interaction between the management server and Xen Server depends on XAPI, and the interaction with vCenter and ESX depends on HTTP.

7. Deployment diagram:

Zone:Zone corresponds to a real data center, which is the largest unit in CloudStack.

The Pod:Pod corresponds to a rack. Machines in the same pod are in the same subnet (network segment).

Cluster:Cluster is a cluster of hosts. Hosts in the same cluster have the same hardware, the same Hypervisor, and share the same storage. Virtual machines in the same cluster can be migrated from one host to another without interruption.

Host:Host is the running virtual machine (VM) host.

That is, in terms of inclusion relationship, a zone contains multiple pod, a pod contains multiple cluster, and a cluster contains multiple host.

There are two types of storage in CloudStack:

Primary storage: primary storage is associated with cluster and provides disk volumes for all virtual machines of hosts in that cluster. An cluster has at least one primary storage and is deployed close to the host to provide high performance.

Secondary storage: secondary storage is associated with zone, which stores template files, ISO images, and disk volume snapshots.

8. Provide point (Pods):

A provisioning point usually represents a rack, and the hosts in the cabinet are on the same subnet, and each area must contain one or more provisioning points. The provisioning point contains the host and the primary storage server. CloudStack's internal management communications are configured with a reserved IP address range. The reserved IP range must be unique for each area in the cloud.

9. Clusters:

Cluster is a cluster of hosts.

Hosts in the same cluster have the same hardware, the same Hypervisor, and share the same storage. Virtual machines in the same cluster can be migrated from one host to another without interruption.

The cluster consists of one or more hosts and one or more primary storage servers. The size of the cluster depends on the underlying virtual machine software. In most cases, there is basically no suggestion. When using VMware, each VMware cluster is managed by a vCenter server. The administrator must register vCenter with this product. There can be multiple vCenter servers under each zone. Each vCenter server may manage multiple VMware clusters

10. Host (Hosts):

Host is the running virtual machine (VM) host.

The host is a stand-alone computer. The host runs the guest virtual machine and provides its corresponding computing resources. Each host has virtual machine software to run the guest virtual machine. For example, a server with kvm support enabled, a Citrix XenServer server, or an ESXi server can be used as a host.

The host is the smallest organizational unit in the CloudStack deployment. The host is included in the cluster, and the cluster belongs to the provisioning point, while the region contains the provisioning point (that is, zone > pod > cluster > host). The new host can be added at any time to provide more resources to guest virtual machines. CloudStack automatically detects the number of cpu and memory resources of the host. The host is not visible to the end user. End users cannot decide which host their virtual machines are assigned to.

11. Storage (Primary Storage):

Primary storage is associated with cluster and provides disk volumes for all virtual machines of hosts in that cluster. An cluster has at least one primary storage and is deployed close to the host to provide high performance.

ISCSI and FC-San storage are loaded into Clustered LVM format in Xenserver, which does not support storage overconfiguration. If the storage itself supports XenServer thin-provisioning,CloudStack, it can also support storage overallocation.

In the global configuration, there is a storage.overprovisioning.factor entry to configure the proportion of overmatches. The default is 2, which supports an overmatched storage format, and the storage that can be used is N times that of that storage.

After the configuration is complete, you can view the storage information in the Dashboard of UI. The Primary Storage Allocated entry is the sum of all primary storage after overallocation, and the Storage entry is the sum of the actual size of all primary storage.

12. Secondary storage (Secondary Storage):

Secondary storage virtual machine (secondary Storage VM) referred to as ssvm, as a kind of system virtual machine, plays a very important role in cloudstack, without which many functions can not be realized.

To put it simply, ssvm is mainly used to manage secondary storage, that is, all operations related to secondary storage will be completed through it. Each resource domain can have more than one SSVM, and when the SSVM is deleted or stopped, it is automatically rebuilt and started.

Cloudstack accesses ssvm directly through ssh access. A private key of ssh has been implanted in the system virtual machine template. At this time, cloudstack only needs to access through its own public key, port 3922. Here the mechanism of xen and vmware is somewhat different. Because the default vmware forbids ssh login, for vmware, you can access ssvm public ip directly through cloudstack's management server. After configuring ssvm, cloudstack causes ssvm to regenerate a pair of public key and private key, and later uses the new key to access ssvm.

In ssvm, there is a java process that is specifically responsible for communicating with port 8250 of cloudstack, and this java process, and related shell scripts are all injected by cloudstack after creating the ssvm, such as vmware, there will be a system.iso, which stores all the files needed by the virtual machine of the system, and after secondary storage on the mount, the file will be copied to ssvm, decompressed in ssvm, and stored in the specified path.

13. What are the specific things in the secondary storage?

Secondary storage is associated with zone, which stores template files, ISO images, and disk volume snapshots. In other words, these resources are managed through SSVM.

①, template: the operating system image of the virtual machine can be started, including other configuration information such as installed applications.

②, ISO image: a disk image that contains operating system data or boot media.

③, Snapshot of disk Volume: a stored copy of virtual machine data that can be used to recover data or create new templates.

14. Ssvm manages secondary storage.

Ssvm manages the resources stored in the secondary storage. First, ssvm will mount the secondary storage locally, and then the operation on the secondary storage will be converted into the operation on the local folder. Functionally, ssvm is responsible for managing snapshot, volume, iso and template. Below, we will explain how to manage these resources from the perspectives of uploading, downloading, querying and deleting.

①, upload resources:

When the user chooses to upload the resource, management server passes the url to ssvm so that ssvm can download the resource from the specified url through wget.

②, download Resources:

When a user chooses to download a specified resource, management server first looks up the path corresponding to the resource from the database and passes the path to ssvm,ssvm to use the built-in apache server to provide resource upload service. In this way, users can download the resources they need through ssvm.

③, query resources:

Ssvm uploads its status information to management server on a regular basis.

④, delete resources:

Because the secondary storage has been mounted in the ssvm, it can delete the contents of the secondary storage directly.

15. How to verify ssvm?

There is a ssvm-check.sh in ssvm, and this shell file is mainly responsible for verifying the relevant configuration of ssvm. The verification contents include: dns, secondary storage of mount, connection to management server, related java processes.

16. Cloudstack network traffic type:

The design and planning of network is a highlight of CloudStack, and it is also one of the main reasons why CloudStack is widely used in business. This article deeply discusses the design of network in CloudStack.

Management, public, customer and storage networks are designed in CloudStack according to different types of data traffic, which can be referred to as PMGS (Public, Management, Guest, Storage) network for short.

①, Public Network (Public Network)

When the virtual machine needs to access the Internet or external network, it needs to go through the public network, which means that the customer virtual machine must be assigned some form of external network IP. Users can get an IP on the UI of CloudStack to do NAT mapping, or they can do load balancing between Guest and Public. All Hypervisor need to share Public VLan to ensure external access of virtual machines.

②, Guest Network (Guest Network)

End users generate Guest traffic when running virtual machine instances created by CloudStack, and the virtual machine instances communicate with each other through the customer network.

③, Management Network (Management Network)

CloudStack internal resources communicate with each other to generate Management traffic, including the communication between the management server node and the Hypervisor cluster, with the system virtual machine or with other components, etc. When the size of the cluster is small, the management traffic only takes up a small amount of bandwidth.

④, storage network (Storage Network)

Interconnection traffic between primary storage and Hypervisor; Stroage traffic is also generated between primary and secondary storage, such as the movement of virtual machine templates and snapshots.

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