Oracle® Linux Ksplice User's Guide
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Oracle® Linux Administrator's Solutions Guide for Release 6
Oracle® Linux Administrator's Solutions Guide for Release 6 E37355-64 August 2017 Oracle Legal Notices Copyright © 2012, 2017, Oracle and/or its affiliates. All rights reserved. This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited. The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing. If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, then the following notice is applicable: U.S. GOVERNMENT END USERS: Oracle programs, including any operating system, integrated software, any programs installed on the hardware, and/or documentation, delivered to U.S. Government end users are "commercial computer software" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, use, duplication, disclosure, modification, and adaptation of the programs, including any operating system, integrated software, any programs installed on the hardware, and/or documentation, shall be subject to license terms and license restrictions applicable to the programs. No other rights are granted to the U.S. -
Flexible Lustre Management
Flexible Lustre management Making less work for Admins ORNL is managed by UT-Battelle for the US Department of Energy How do we know Lustre condition today • Polling proc / sysfs files – The knocking on the door model – Parse stats, rpc info, etc for performance deviations. • Constant collection of debug logs – Heavy parsing for common problems. • The death of a node – Have to examine kdumps and /or lustre dump Origins of a new approach • Requirements for Linux kernel integration. – No more proc usage – Migration to sysfs and debugfs – Used to configure your file system. – Started in lustre 2.9 and still on going. • Two ways to configure your file system. – On MGS server run lctl conf_param … • Directly accessed proc seq_files. – On MSG server run lctl set_param –P • Originally used an upcall to lctl for configuration • Introduced in Lustre 2.4 but was broken until lustre 2.12 (LU-7004) – Configuring file system works transparently before and after sysfs migration. Changes introduced with sysfs / debugfs migration • sysfs has a one item per file rule. • Complex proc files moved to debugfs • Moving to debugfs introduced permission problems – Only debugging files should be their. – Both debugfs and procfs have scaling issues. • Moving to sysfs introduced the ability to send uevents – Item of most interest from LUG 2018 Linux Lustre client talk. – Both lctl conf_param and lctl set_param –P use this approach • lctl conf_param can set sysfs attributes without uevents. See class_modify_config() – We get life cycle events for free – udev is now involved. What do we get by using udev ? • Under the hood – uevents are collect by systemd and then processed by udev rules – /etc/udev/rules.d/99-lustre.rules – SUBSYSTEM=="lustre", ACTION=="change", ENV{PARAM}=="?*", RUN+="/usr/sbin/lctl set_param '$env{PARAM}=$env{SETTING}’” • You can create your own udev rule – http://reactivated.net/writing_udev_rules.html – /lib/udev/rules.d/* for examples – Add udev_log="debug” to /etc/udev.conf if you have problems • Using systemd for long task. -
Adaptive Android Kernel Live Patching
Adaptive Android Kernel Live Patching Yue Chen Yulong Zhang Zhi Wang Liangzhao Xia Florida State University Baidu X-Lab Florida State University Baidu X-Lab Chenfu Bao Tao Wei Baidu X-Lab Baidu X-Lab Abstract apps contain sensitive personal data, such as bank ac- counts, mobile payments, private messages, and social Android kernel vulnerabilities pose a serious threat to network data. Even TrustZone, widely used as the se- user security and privacy. They allow attackers to take cure keystore and digital rights management in Android, full control over victim devices, install malicious and un- is under serious threat since the compromised kernel en- wanted apps, and maintain persistent control. Unfortu- ables the attacker to inject malicious payloads into Trust- nately, most Android devices are never timely updated Zone [42, 43]. Therefore, Android kernel vulnerabilities to protect their users from kernel exploits. Recent An- pose a serious threat to user privacy and security. droid malware even has built-in kernel exploits to take Tremendous efforts have been put into finding (and ex- advantage of this large window of vulnerability. An ef- ploiting) Android kernel vulnerabilities by both white- fective solution to this problem must be adaptable to lots hat and black-hat researchers, as evidenced by the sig- of (out-of-date) devices, quickly deployable, and secure nificant increase of kernel vulnerabilities disclosed in from misuse. However, the fragmented Android ecosys- Android Security Bulletin [3] in recent years. In ad- tem makes this a complex and challenging task. dition, many kernel vulnerabilities/exploits are publicly To address that, we systematically studied 1;139 An- available but never reported to Google or the vendors, droid kernels and all the recent critical Android ker- let alone patched (e.g., exploits in Android rooting nel vulnerabilities. -
CSE421 Midterm Solutions —SOLUTION SET— 09 Mar 2012
CSE421 Midterm Solutions —SOLUTION SET— 09 Mar 2012 This midterm exam consists of three types of questions: 1. 10 multiple choice questions worth 1 point each. These are drawn directly from lecture slides and intended to be easy. 2. 6 short answer questions worth 5 points each. You can answer as many as you want, but we will give you credit for your best four answers for a total of up to 20 points. You should be able to answer the short answer questions in four or five sentences. 3. 2 long answer questions worth 20 points each. Please answer only one long answer question. If you answer both, we will only grade one. Your answer to the long answer should span a page or two. Please answer each question as clearly and succinctly as possible. Feel free to draw pic- tures or diagrams if they help you to do so. No aids of any kind are permitted. The point value assigned to each question is intended to suggest how to allocate your time. So you should work on a 5 point question for roughly 5 minutes. CSE421 Midterm Solutions 09 Mar 2012 Multiple Choice 1. (10 points) Answer all ten of the following questions. Each is worth one point. (a) In the story that GWA (Geoff) began class with on Monday, March 4th, why was the Harvard student concerned about his grade? p He never attended class. He never arrived at class on time. He usually fell asleep in class. He was using drugs. (b) All of the following are inter-process (IPC) communication mechanisms except p shared files. -
Version 7.8-Systemd
Linux From Scratch Version 7.8-systemd Created by Gerard Beekmans Edited by Douglas R. Reno Linux From Scratch: Version 7.8-systemd by Created by Gerard Beekmans and Edited by Douglas R. Reno Copyright © 1999-2015 Gerard Beekmans Copyright © 1999-2015, Gerard Beekmans All rights reserved. This book is licensed under a Creative Commons License. Computer instructions may be extracted from the book under the MIT License. Linux® is a registered trademark of Linus Torvalds. Linux From Scratch - Version 7.8-systemd Table of Contents Preface .......................................................................................................................................................................... vii i. Foreword ............................................................................................................................................................. vii ii. Audience ............................................................................................................................................................ vii iii. LFS Target Architectures ................................................................................................................................ viii iv. LFS and Standards ............................................................................................................................................ ix v. Rationale for Packages in the Book .................................................................................................................... x vi. Prerequisites -
Precise Garbage Collection for C
Precise Garbage Collection for C Jon Rafkind Adam Wick John Regehr Matthew Flatt University of Utah Galois, Inc. University of Utah University of Utah [email protected] [email protected] [email protected] mfl[email protected] Abstract no-ops. The resulting program usually runs about as well as before, Magpie is a source-to-source transformation for C programs that but without the ongoing maintenance burden of manual memory enables precise garbage collection, where precise means that inte- management. In our experience, however, conservative GC works gers are not confused with pointers, and the liveness of a pointer poorly for long-running programs, such as a web server, a program- is apparent at the source level. Precise GC is primarily useful for ming environment, or an operating system kernel. For such pro- long-running programs and programs that interact with untrusted grams, conservative GC can trigger unbounded memory use due to components. In particular, we have successfully deployed precise linked lists [Boehm 2002] that manage threads and continuations; GC in the C implementation of a language run-time system that was this problem is usually due to liveness imprecision [Hirzel et al. originally designed to use conservative GC. We also report on our 2002], rather than type imprecision. Furthermore, the programs experience in transforming parts of the Linux kernel to use precise are susceptible to memory-exhaustion attack from malicious code GC instead of manual memory management. (e.g., user programs or untrusted servlets) that might be otherwise restricted through a sandbox [Wick and Flatt 2004]. Categories and Subject Descriptors D.4.2 [Storage Manage- This paper describes our design of and experience with a GC ment]: Garbage Collection for C that is less conservative. -
Man Pages Section 3 Library Interfaces and Headers
man pages section 3: Library Interfaces and Headers Part No: 816–5173–16 September 2010 Copyright © 2010, Oracle and/or its affiliates. All rights reserved. This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited. The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing. If this is software or related software documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, the following notice is applicable: U.S. GOVERNMENT RIGHTS Programs, software, databases, and related documentation and technical data delivered to U.S. Government customers are “commercial computer software” or “commercial technical data” pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, the use, duplication, disclosure, modification, and adaptation shall be subject to the restrictions and license terms setforth in the applicable Government contract, and, to the extent applicable by the terms of the Government contract, the additional rights set forth in FAR 52.227-19, Commercial Computer Software License (December 2007). Oracle America, Inc., 500 Oracle Parkway, Redwood City, CA 94065. -
Protecting Your Linux Systems with Oracle Ksplice
Staying Ahead of Cyberthreats: Protecting Your Linux Systems with Oracle Ksplice The Advantages Of Zero-Downtime Patching April 23, 2020 Copyright © 2020, Oracle and/or its affiliates Public TABLE OF CONTENTS Introduction 2 Why Patching Matters 2 About Oracle Ksplice 3 Other Benefits 3 Conclusion 4 Learn More 4 1 WHITE PAPER | Staying Ahead of Cyberthreats: Protecting Your Linux Systems Copyright © 2020, Oracle and/or its affiliates |Public INTRODUCTION IT systems require regular patching for security, performance, and compliance reasons. For Linux operating system (OS) kernel updates, which include “Availability requirements important new security enhancements and bug fixes, releases happen about 1 are on the rise for once per month. These updates help keep systems current with the latest organizations undergoing innovations. However, manually patching systems has many inherent digital transformations. challenges and difficulties which tends to delay their timely application. For this Downtimes are costly, reason, zero-downtime patching solutions for Linux, like Oracle Ksplice, are with unplanned becoming essential tools. In this paper, Oracle Ksplice’s capabilities and many infrastructure downtimes advantages are explained. costing $100,000 per hour on an average. With Why Patching Matters the possibility of every organization being a Inadequate patch management can leave loopholes in the IT infrastructure leading to target for cyberattacks various security and performance issues. Ideally, patches should be applied shortly after and attackers moving very release to ensure the latest system protections. Patching typically requires downtime quickly to exploit system which, depending on operations, can require weeks or months of advanced planning. vulnerabilities, IDC Most Linux patching also traditionally happens at the disk level for file systems, which has recommends several disadvantages. -
Scalability of VM Provisioning Systems
Scalability of VM Provisioning Systems Mike Jones, Bill Arcand, Bill Bergeron, David Bestor, Chansup Byun, Lauren Milechin, Vijay Gadepally, Matt Hubbell, Jeremy Kepner, Pete Michaleas, Julie Mullen, Andy Prout, Tony Rosa, Siddharth Samsi, Charles Yee, Albert Reuther Lincoln Laboratory Supercomputing Center MIT Lincoln Laboratory Lexington, MA, USA Abstract—Virtual machines and virtualized hardware have developed a technique based on binary code substitution been around for over half a century. The commoditization of the (binary translation) that enabled the execution of privileged x86 platform and its rapidly growing hardware capabilities have (OS) instructions from virtual machines on x86 systems [16]. led to recent exponential growth in the use of virtualization both Another notable effort was the Xen project, which in 2003 used in the enterprise and high performance computing (HPC). The a jump table for choosing bare metal execution or virtual startup time of a virtualized environment is a key performance machine execution of privileged (OS) instructions [17]. Such metric for high performance computing in which the runtime of projects prompted Intel and AMD to add the VT-x [19] and any individual task is typically much shorter than the lifetime of AMD-V [18] virtualization extensions to the x86 and x86-64 a virtualized service in an enterprise context. In this paper, a instruction sets in 2006, further pushing the performance and methodology for accurately measuring the startup performance adoption of virtual machines. on an HPC system is described. The startup performance overhead of three of the most mature, widely deployed cloud Virtual machines have seen use in a variety of applications, management frameworks (OpenStack, OpenNebula, and but with the move to highly capable multicore CPUs, gigabit Eucalyptus) is measured to determine their suitability for Ethernet network cards, and VM-aware x86/x86-64 operating workloads typically seen in an HPC environment. -
Part I: Unix Signals
Part I: Unix Signals 1 Stopping a Program What if you run this program? int main () { while (1); printf("bye\n"); return 0; } What happens if you hit Ctl-C? Could you make Ctl-C print ªbyeº before exiting? 2-4 Signals A shell handles Ctl-C by sending the SIGINT signal to a process The sigaction() function can be used to install a signal handler See bye.c and bye2.c 5 Some Other Signals SIGHUP terminal is gone SIGQUIT please quit SIGKILL force quit (cannot handle) SIGSEGV seg fault SIGALRM timer expired SIGPIPE write to pipe with closed read end SIGCHLD child completed 6 Timers Use setitimer() to start a timer See timer.c and timer2.c... 7 Signal Handlers and Races Beware! Ð a signal handler is practically a thread Use sigprocmask() to (un)block signals See timer3.c 8 Part II: Deadlock · Conditions · Prevention · Detection 9 Deadlock is when two or more threads are waiting for an event that can only be generated by these same threads printer->Wait(); disk->Wait(); disk->Wait(); printer->Wait(); // copy from disk // copy from disk // to printer // to printer printer->Signal(); printer->Signal(); disk->Signal(); disk->Signal(); Deadlock can occur anytime threads acquire multiple resources (printers, disks, etc.), perform work, and then release their resources 10 Deadlock 11 Deadlock 12 Deadlock Examples · Linux: In-kernel memory allocator runs out of pages, causing an ªout of memory handlerº to run, which calls a function that tries to allocate a page. · Windows 2000: The OS keeps a pool of ªworker threadsº waiting to do work; one worker thread submits a job to another worker thread, but there are no free worker-thread slots. -
Container and Kernel-Based Virtual Machine (KVM) Virtualization for Network Function Virtualization (NFV)
Container and Kernel-Based Virtual Machine (KVM) Virtualization for Network Function Virtualization (NFV) White Paper August 2015 Order Number: 332860-001US YouLegal Lines andmay Disclaimers not use or facilitate the use of this document in connection with any infringement or other legal analysis concerning Intel products described herein. You agree to grant Intel a non-exclusive, royalty-free license to any patent claim thereafter drafted which includes subject matter disclosed herein. No license (express or implied, by estoppel or otherwise) to any intellectual property rights is granted by this document. All information provided here is subject to change without notice. Contact your Intel representative to obtain the latest Intel product specifications and roadmaps. The products described may contain design defects or errors known as errata which may cause the product to deviate from published specifications. Current characterized errata are available on request. Copies of documents which have an order number and are referenced in this document may be obtained by calling 1-800-548-4725 or by visiting: http://www.intel.com/ design/literature.htm. Intel technologies’ features and benefits depend on system configuration and may require enabled hardware, software or service activation. Learn more at http:// www.intel.com/ or from the OEM or retailer. Results have been estimated or simulated using internal Intel analysis or architecture simulation or modeling, and provided to you for informational purposes. Any differences in your system hardware, software or configuration may affect your actual performance. For more complete information about performance and benchmark results, visit www.intel.com/benchmarks. Tests document performance of components on a particular test, in specific systems. -
Automatic Handling of Global Variables for Multi-Threaded MPI Programs
Automatic Handling of Global Variables for Multi-threaded MPI Programs Gengbin Zheng, Stas Negara, Celso L. Mendes, Laxmikant V. Kale´ Eduardo R. Rodrigues Department of Computer Science Institute of Informatics University of Illinois at Urbana-Champaign Federal University of Rio Grande do Sul Urbana, IL 61801, USA Porto Alegre, Brazil fgzheng,snegara2,cmendes,[email protected] [email protected] Abstract— necessary to privatize global and static variables to ensure Hybrid programming models, such as MPI combined with the thread-safety of an application. threads, are one of the most efficient ways to write parallel ap- In high-performance computing, one way to exploit multi- plications for current machines comprising multi-socket/multi- core nodes and an interconnection network. Global variables in core platforms is to adopt hybrid programming models that legacy MPI applications, however, present a challenge because combine MPI with threads, where different programming they may be accessed by multiple MPI threads simultaneously. models are used to address issues such as multiple threads Thus, transforming legacy MPI applications to be thread-safe per core, decreasing amount of memory per core, load in order to exploit multi-core architectures requires proper imbalance, etc. When porting legacy MPI applications to handling of global variables. In this paper, we present three approaches to eliminate these hybrid models that involve multiple threads, thread- global variables to ensure thread-safety for an MPI program. safety of the applications needs to be addressed again. These approaches include: (a) a compiler-based refactoring Global variables cause no problem with traditional MPI technique, using a Photran-based tool as an example, which implementations, since each process image contains a sep- automates the source-to-source transformation for programs arate instance of the variable.