3bb318bab9
1. Problem description
In Apache CloudStack (ACS), when a VM is deployed in a host with the KVM hypervisor, an XML file is created in the assigned host, which has a property shares that defines the weight of the VM to access the host CPU. The value of this property has no unit, and it is a relative measure to calculate how much CPU a given VM will have in the host. However, this value has a limit, which depends on the version of cgroup utilized by the host's kernel. The problem lies at the range value of shares that varies between both versions: [2, 264144] for cgroups version 1; and [1, 10000] for cgroups version 2. Currently, ACS calculates the value of shares using Equation 1, presented below, where CPU is the number of cores and speed is the CPU frequency; both specified in the VM's compute offering. Therefore, if a compute offering has, for example, 6 cores at 2 GHz, the shares value will be 12000 and an exception will be thrown by libvirt if the host utilizes cgroup v2. The second version is becoming the default one in current Linux distributions; thus, it is necessary to address this limitation.
Equation 1
shares = CPU * speed
Fixes: #6744
2. Proposed changes
To address the problem described, we propose to apply a scale conversion considering the max shares of the host. Using the same formula currently utilized by ACS, it is possible to calculate the maximum shares of a VM for a given host. In other words, using the number of cores and the nominal speed of the host's CPU as the upper limit of shares allowed to a VM. Then, this value will be scaled to the allowed interval of [1, 10000] of cgroup v2 by using a linear scale conversion.
The VM shares would be calculated as Equation 2, presented below, where VM requested shares is the requested shares value calculated using Equation 1, cgroup upper limit is fixed with a value of 10000 (cgroups v2 upper limit), and host max shares is the maximum shares value of the host, calculated using Equation 1. Using Equation 2, the only case where a VM passes the cgroup v2 limit is when the user requests more resources than the host has, which is not possible with the current implementation of ACS.
Equation 2
shares = (VM requested shares * cgroup upper limit)/host max shares
To implement the proposal, the following APIs will be updated: deployVirtualMachine, migrateVirtualMachine and scaleVirtualMachine. When a VM is being deployed, a new verification will be added to find a suitable host. The max shares of each host will be calculated, and the VM calculated shares will be verified if it does not surpass the host's value. Likewise, the migration of VMs will have a similar new verification. Lastly, the scale of VMs will also have the same verification for the VM's host.
To determine the max shares of a given host, we will use the same equation currently used in ACS for calculating the shares of VMs, presented in Section 1. When Equation 1 is used to determine the maximum shares of a host, CPU is the number of cores of the host, and speed is the nominal CPU speed, i.e., considering the CPU's base frequency.
It is important to note that these changes are only for hosts with the KVM hypervisor using cgroup v2 for now.
Apache CloudStack 
Apache CloudStack is open source software designed to deploy and manage large networks of virtual machines, as a highly available, highly scalable Infrastructure as a Service (IaaS) cloud computing platform. CloudStack is used by a number of service providers to offer public cloud services, and by many companies to provide an on-premises (private) cloud offering, or as part of a hybrid cloud solution.
CloudStack is a turnkey solution that includes the entire "stack" of features most organizations want with an IaaS cloud: compute orchestration, Network-as-a-Service, user and account management, a full and open native API, resource accounting, and a first-class User Interface (UI).
CloudStack currently supports the most popular hypervisors: VMware vSphere, KVM, XenServer, XenProject and Hyper-V as well as OVM and LXC containers.
Users can manage their cloud with an easy to use Web interface, command line tools, and/or a full-featured query based API.
For more information on Apache CloudStack, please visit the website
Who Uses CloudStack?
-
There are more than 150 known organizations using Apache CloudStack (or a commercial distribution of CloudStack). Our users include many major service providers running CloudStack to offer public cloud services, product vendors who incorporate or integrate with CloudStack in their own products, organizations who have used CloudStack to build their own private clouds, and systems integrators that offer CloudStack related services.
-
See our case studies highlighting successful deployments of Apache CloudStack.
-
See the up-to-date list of current users.
-
If you are using CloudStack in your organization and your company is not listed above, please complete our brief adoption survey. We're happy to keep your company name anonymous if you require.
Demo
See the project user-interface QA website that runs CloudStack against simulator hypervisor: https://qa.cloudstack.cloud/simulator/ (admin:password)
Getting Started
- Download a released version
- Build from source with the instructions in the INSTALL.md file.
Getting Source Repository
Apache CloudStack project uses Git. The official Git repository is at:
https://gitbox.apache.org/repos/asf/cloudstack.git
And a mirror is hosted on GitHub:
https://github.com/apache/cloudstack
The GitHub mirror is strictly read only and provides convenience to users and developers to explore the code and for the community to accept contributions via GitHub pull requests.
Documentation
- Project Documentation
- Release notes
- Developer wiki
- Design documents
- API documentation
- How to contribute
News and Events
Getting Involved and Contributing
Interested in helping out with Apache CloudStack? Great! We welcome participation from anybody willing to work The Apache Way and make a contribution. Note that you do not have to be a developer in order to contribute to Apache CloudStack. We need folks to help with documentation, translation, promotion etc. See our contribution page.
If you're interested in learning more or participating in the Apache CloudStack project, the mailing lists are the best way to do that. While the project has several communications channels, the mailing lists are the most active and the official channels for making decisions about the project itself.
Mailing lists:
- Development Mailing List
- Users Mailing List
- Commits Mailing List
- Issues Mailing List
- Marketing Mailing List
Report and/or check bugs on GitHub and check our developer page for contributing code.
Reporting Security Vulnerabilities
If you've found an issue that you believe is a security vulnerability in a
released version of CloudStack, please report it to security@apache.org with
details about the vulnerability, how it might be exploited, and any additional
information that might be useful.
For more details, please visit our security page.
License
Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
Please see the LICENSE file included in the root directory of the source tree for extended license details.
Notice of Cryptographic Software
This distribution includes cryptographic software. The country in which you currently reside may have restrictions on the import, possession, use, and/or re-export to another country, of encryption software. BEFORE using any encryption software, please check your country's laws, regulations and policies concerning the import, possession, or use, and re-export of encryption software, to see if this is permitted. See http://www.wassenaar.org/ for more information.
The U.S. Government Department of Commerce, Bureau of Industry and Security (BIS), has classified this software as Export Commodity Control Number (ECCN) 5D002.C.1, which includes information security software using or performing cryptographic functions with asymmetric algorithms. The form and manner of this Apache Software Foundation distribution makes it eligible for export under the License Exception ENC Technology Software Unrestricted (TSU) exception (see the BIS Export Administration Regulations, Section 740.13) for both object code and source code.
The following provides more details on the included cryptographic software:
- CloudStack makes use of JaSypt cryptographic libraries.
- CloudStack has a system requirement of MySQL, and uses native database encryption functionality.
- CloudStack makes use of the Bouncy Castle general-purpose encryption library.
- CloudStack can optionally interact with and control OpenSwan-based VPNs.
- CloudStack has a dependency on and makes use of JSch - a java SSH2 implementation.