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When I create the instance in the dashboard, I get error:
当我在仪表板中创建实例时，我收到错误：
No valid host was found. There are not enough hosts available.
In the /var/log/nova/nova-conductor.log file, there is the log:
在/var/log/nova/nova-conductor.log文件中，有以下日志：
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退出2017-08-05 00:22:29.046 3834 WARNING nova.scheduler.utils [req-89c159c7-b40a-43eb-8f0d-9306eb73e83a 2a5fa182fb1b459980db09cd1572850e 0d5998f2f7ec4c4892a32e06bafb19df - - -] Failed to compute_task_build_instances: No valid host was found. There are not enough hosts available.
Traceback (most recent call last):
File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/server.py", line 199, in inner
return func(*args, **kwargs)
File "/usr/lib/python2.7/site-packages/nova/scheduler/manager.py", line 104, in select_destinations
dests = self.driver.select_destinations(ctxt, spec_obj)
File "/usr/lib/python2.7/site-packages/nova/scheduler/filter_scheduler.py", line 74, in select_destinations
raise exception.NoValidHost(reason=reason)
NoValidHost: No valid host was found. There are not enough hosts available.
2017-08-05 00:22:29.048 3834 WARNING nova.scheduler.utils [req-89c159c7-b40a-43eb-8f0d-9306eb73e83a 2a5fa182fb1b459980db09cd1572850e 0d5998f2f7ec4c4892a32e06bafb19df - - -] [instance: 2011e343-c8fc-4ed0-8148-b0d2b5ba37c3] Setting instance to ERROR state.
2017-08-05 00:22:30.785 3834 WARNING oslo_config.cfg [req-89c159c7-b40a-43eb-8f0d-9306eb73e83a 2a5fa182fb1b459980db09cd1572850e 0d5998f2f7ec4c4892a32e06bafb19df - - -] Option "auth_plugin" from group "neutron" is deprecated. Use option "auth_type" from group "neutron".
And I searched the SO, find a related post:Openstack-Devstack: Can't create instance, There are not enough hosts available
我搜索了SO，找到了一个相关的帖子：OpenStack-DevStack：无法创建实例，没有足够的主机可用
I checked the free_ram_mb in mysql:
我检查了MySQL中的Free_ram_mb：
MariaDB [nova]> select * from compute_nodes \G;
*************************** 1. row ***************************
created_at: 2017-08-04 12:44:26
updated_at: 2017-08-04 13:51:35
deleted_at: NULL
id: 4
service_id: NULL
vcpus: 8
memory_mb: 7808
local_gb: 19
vcpus_used: 0
memory_mb_used: 512
local_gb_used: 0
hypervisor_type: QEMU
hypervisor_version: 1005003
cpu_info: {"vendor": "Intel", "model": "Broadwell", "arch": "x86_64", "features": ["smap", "avx", "clflush", "sep", "rtm", "vme", "invpcid", "msr", "fsgsbase", "xsave", "pge", "erms", "hle", "cmov", "tsc", "smep", "pcid", "pat", "lm", "abm", "adx", "3dnowprefetch", "nx", "fxsr", "syscall", "sse4.1", "pae", "sse4.2", "pclmuldq", "fma", "tsc-deadline", "mmx", "osxsave", "cx8", "mce", "de", "rdtscp", "ht", "pse", "lahf_lm", "rdseed", "popcnt", "mca", "pdpe1gb", "apic", "sse", "f16c", "ds", "invtsc", "pni", "aes", "avx2", "sse2", "ss", "hypervisor", "bmi1", "bmi2", "ssse3", "fpu", "cx16", "pse36", "mtrr", "movbe", "rdrand", "x2apic"], "topology": {"cores": 2, "cells": 1, "threads": 1, "sockets": 4}}
disk_available_least: 18
free_ram_mb: 7296
free_disk_gb: 19
current_workload: 0
running_vms: 0
hypervisor_hostname: ha-node1
deleted: 0
host_ip: 192.168.8.101
supported_instances: [["i686", "qemu", "hvm"], ["x86_64", "qemu", "hvm"]]
pci_stats: {"nova_object.version": "1.1", "nova_object.changes": ["objects"], "nova_object.name": "PciDevicePoolList", "nova_object.data": {"objects": []}, "nova_object.namespace": "nova"}
metrics: []
extra_resources: NULL
stats: {}
numa_topology: NULL
host: ha-node1
ram_allocation_ratio: 3
cpu_allocation_ratio: 16
uuid: 9113940b-7ec9-462d-af06-6988dbb6b6cf
disk_allocation_ratio: 1
*************************** 2. row ***************************
created_at: 2017-08-04 12:44:34
updated_at: 2017-08-04 13:50:47
deleted_at: NULL
id: 6
service_id: NULL
vcpus: 8
memory_mb: 7808
local_gb: 19
vcpus_used: 0
memory_mb_used: 512
local_gb_used: 0
hypervisor_type: QEMU
hypervisor_version: 1005003
cpu_info: {"vendor": "Intel", "model": "Broadwell", "arch": "x86_64", "features": ["smap", "avx", "clflush", "sep", "rtm", "vme", "invpcid", "msr", "fsgsbase", "xsave", "pge", "erms", "hle", "cmov", "tsc", "smep", "pcid", "pat", "lm", "abm", "adx", "3dnowprefetch", "nx", "fxsr", "syscall", "sse4.1", "pae", "sse4.2", "pclmuldq", "fma", "tsc-deadline", "mmx", "osxsave", "cx8", "mce", "de", "rdtscp", "ht", "pse", "lahf_lm", "rdseed", "popcnt", "mca", "pdpe1gb", "apic", "sse", "f16c", "ds", "invtsc", "pni", "aes", "avx2", "sse2", "ss", "hypervisor", "bmi1", "bmi2", "ssse3", "fpu", "cx16", "pse36", "mtrr", "movbe", "rdrand", "x2apic"], "topology": {"cores": 2, "cells": 1, "threads": 1, "sockets": 4}}
disk_available_least: 18
free_ram_mb: 7296
free_disk_gb: 19
current_workload: 0
running_vms: 0
hypervisor_hostname: ha-node2
deleted: 0
host_ip: 192.168.8.102
supported_instances: [["i686", "qemu", "hvm"], ["x86_64", "qemu", "hvm"]]
pci_stats: {"nova_object.version": "1.1", "nova_object.changes": ["objects"], "nova_object.name": "PciDevicePoolList", "nova_object.data": {"objects": []}, "nova_object.namespace": "nova"}
metrics: []
extra_resources: NULL
stats: {}
numa_topology: NULL
host: ha-node2
ram_allocation_ratio: 3
cpu_allocation_ratio: 16
uuid: 32b574df-52ac-43dc-87f8-353350449076
disk_allocation_ratio: 1
2 rows in set (0.00 sec)
You see the free_ram_mb: 7296, I just want to create a 512mb VM, but failed.
您可以看到Free_ram_mb：7296，我只想创建一个512MB的VM，但失败了。
EDIT-1
编辑-1
The nova services all are up:
新星服务全部启动：
[root@ha-node1 ~]# nova service-list
+----+------------------+----------+----------+---------+-------+----------------------------+-----------------+
| Id | Binary | Host | Zone | Status | State | Updated_at | Disabled Reason |
+----+------------------+----------+----------+---------+-------+----------------------------+-----------------+
| 2 | nova-consoleauth | ha-node3 | internal | enabled | up | 2017-08-05T14:20:25.000000 | - |
| 5 | nova-conductor | ha-node3 | internal | enabled | up | 2017-08-05T14:20:29.000000 | - |
| 7 | nova-cert | ha-node3 | internal | enabled | up | 2017-08-05T14:20:23.000000 | - |
| 15 | nova-scheduler | ha-node3 | internal | enabled | up | 2017-08-05T14:20:20.000000 | - |
| 22 | nova-cert | ha-node1 | internal | enabled | up | 2017-08-05T14:20:26.000000 | - |
| 29 | nova-conductor | ha-node1 | internal | enabled | up | 2017-08-05T14:20:22.000000 | - |
| 32 | nova-consoleauth | ha-node1 | internal | enabled | up | 2017-08-05T14:20:29.000000 | - |
| 33 | nova-consoleauth | ha-node2 | internal | enabled | up | 2017-08-05T14:20:29.000000 | - |
| 36 | nova-scheduler | ha-node1 | internal | enabled | up | 2017-08-05T14:20:30.000000 | - |
| 40 | nova-conductor | ha-node2 | internal | enabled | up | 2017-08-05T14:20:26.000000 | - |
| 44 | nova-cert | ha-node2 | internal | enabled | up | 2017-08-05T14:20:27.000000 | - |
| 46 | nova-scheduler | ha-node2 | internal | enabled | up | 2017-08-05T14:20:28.000000 | - |
| 49 | nova-compute | ha-node2 | nova | enabled | up | 2017-08-05T14:19:35.000000 | - |
| 53 | nova-compute | ha-node1 | nova | enabled | up | 2017-08-05T14:20:05.000000 | - |
+----+------------------+----------+----------+---------+-------+----------------------------+-----------------+
The nova list:
新星名单：
[root@ha-node1 ~]# nova list
+--------------------------------------+------+--------+------------+-------------+----------+
| ID | Name | Status | Task State | Power State | Networks |
+--------------------------------------+------+--------+------------+-------------+----------+
| 20193e58-2c5b-44c6-a98f-a44e2001934f | vm1 | ERROR | - | NOSTATE | |
And the nova show instance:
和新星展示的例子：
[root@ha-node1 ~]# nova show 20193e58-2c5b-44c6-a98f-a44e2001934f
+--------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Property | Value |
+--------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| OS-DCF:diskConfig | AUTO |
| OS-EXT-AZ:availability_zone | nova |
| OS-EXT-SRV-ATTR:host | - |
| OS-EXT-SRV-ATTR:hostname | vm1 |
| OS-EXT-SRV-ATTR:hypervisor_hostname | - |
| OS-EXT-SRV-ATTR:instance_name | instance-00000003 |
| OS-EXT-SRV-ATTR:kernel_id | |
| OS-EXT-SRV-ATTR:launch_index | 0 |
| OS-EXT-SRV-ATTR:ramdisk_id | |
| OS-EXT-SRV-ATTR:reservation_id | r-jct8kkcq |
| OS-EXT-SRV-ATTR:root_device_name | /dev/vda |
| OS-EXT-SRV-ATTR:user_data | - |
| OS-EXT-STS:power_state | 0 |
| OS-EXT-STS:task_state | - |
| OS-EXT-STS:vm_state | error |
| OS-SRV-USG:launched_at | - |
| OS-SRV-USG:terminated_at | - |
| accessIPv4 | |
| accessIPv6 | |
| config_drive | |
| created | 2017-08-05T14:17:54Z |
| description | vm1 |
| fault | {"message": "No valid host was found. There are not enough hosts available.", "code": 500, "details": " File \"/usr/lib/python2.7/site-packages/nova/conductor/manager.py\", line 496, in build_instances |
| | context, request_spec, filter_properties) |
| | File \"/usr/lib/python2.7/site-packages/nova/conductor/manager.py\", line 567, in _schedule_instances |
| | hosts = self.scheduler_client.select_destinations(context, spec_obj) |
| | File \"/usr/lib/python2.7/site-packages/nova/scheduler/utils.py\", line 370, in wrapped |
| | return func(*args, **kwargs) |
| | File \"/usr/lib/python2.7/site-packages/nova/scheduler/client/__init__.py\", line 51, in select_destinations |
| | return self.queryclient.select_destinations(context, spec_obj) |
| | File \"/usr/lib/python2.7/site-packages/nova/scheduler/client/__init__.py\", line 37, in __run_method |
| | return getattr(self.instance, __name)(*args, **kwargs) |
| | File \"/usr/lib/python2.7/site-packages/nova/scheduler/client/query.py\", line 32, in select_destinations |
| | return self.scheduler_rpcapi.select_destinations(context, spec_obj) |
| | File \"/usr/lib/python2.7/site-packages/nova/scheduler/rpcapi.py\", line 126, in select_destinations |
| | return cctxt.call(ctxt, 'select_destinations', **msg_args) |
| | File \"/usr/lib/python2.7/site-packages/oslo_messaging/rpc/client.py\", line 169, in call |
| | retry=self.retry) |
| | File \"/usr/lib/python2.7/site-packages/oslo_messaging/transport.py\", line 97, in _send |
| | timeout=timeout, retry=retry) |
| | File \"/usr/lib/python2.7/site-packages/oslo_messaging/_drivers/amqpdriver.py\", line 464, in send |
| | retry=retry) |
| | File \"/usr/lib/python2.7/site-packages/oslo_messaging/_drivers/amqpdriver.py\", line 455, in _send |
| | raise result |
| | ", "created": "2017-08-05T14:18:14Z"} |
| flavor | m1.tiny (1) |
| hostId | |
| host_status | |
| id | 20193e58-2c5b-44c6-a98f-a44e2001934f |
| image | cirros-0.3.4-x86_64 (202778cd-6b32-4486-9444-c167089d9082) |
| key_name | - |
| locked | False |
| metadata | {} |
| name | vm1 |
| os-extended-volumes:volumes_attached | [] |
| status | ERROR |
| tags | [] |
| tenant_id | 0d5998f2f7ec4c4892a32e06bafb19df |
| updated | 2017-08-05T14:18:16Z |
| user_id | 2a5fa182fb1b459980db09cd1572850e |
+--------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
EDIT-2
编辑-2
The nova-compute.log in the /var/log/nova/ useful information:
/var/log/nova/有用信息中的nova-culte.log：
......
2017-08-05 22:17:42.669 103174 INFO nova.compute.resource_tracker [req-60a062ce-4b3d-4cb7-863e-2f9bba0bc6ec - - - - -] Compute_service record updated for ha-node1:ha-node1
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [req-7dded91f-7497-4d20-ba89-69f867a2a8fb 2a5fa182fb1b459980db09cd1572850e 0d5998f2f7ec4c4892a32e06bafb19df - - -] [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] Instance failed to spawn
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] Traceback (most recent call last):
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 2078, in _build_resources
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] yield resources
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 1920, in _build_and_run_instance
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] block_device_info=block_device_info)
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 2584, in spawn
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] admin_pass=admin_password)
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 2959, in _create_image
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] fileutils.ensure_tree(libvirt_utils.get_instance_path(instance))
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] File "/usr/lib/python2.7/site-packages/oslo_utils/fileutils.py", line 40, in ensure_tree
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] os.makedirs(path, mode)
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] File "/usr/lib64/python2.7/os.py", line 157, in makedirs
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] mkdir(name, mode)
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] OSError: [Errno 13] Permission denied: '/var/lib/nova/instances/20193e58-2c5b-44c6-a98f-a44e2001934f'
2017-08-05 22:18:03.357 103174 ERROR nova.compute.manager [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f]
2017-08-05 22:18:11.563 103174 INFO nova.compute.manager [req-7dded91f-7497-4d20-ba89-69f867a2a8fb 2a5fa182fb1b459980db09cd1572850e 0d5998f2f7ec4c4892a32e06bafb19df - - -] [instance: 20193e58-2c5b-44c6-a98f-a44e2001934f] Terminating instance
....
You should probably start by examining the nova-scheduler logs to see if there is any relevant information there. If you haven't already you may want to enabled debug logging, restart the scheduler, and repeat the experiment. The "no valid hosts" error can be caused by resource availability issues (ram, disk space) and also by nova configuration errors (e.g., you are trying to boot a kvm guest but your host does not support hardware accelerated virtualization).
您可能应该从检查nova-Scheduler日志开始，看看那里是否有任何相关信息。如果您尚未启用调试日志记录，则可能需要重新启动调度程序，然后重复该实验。资源可用性问题(RAM、磁盘空间)和nova配置错误(例如，您正在尝试引导KVM来宾，但您的主机不支持硬件加速的虚拟化)可能会导致“没有有效的主机”错误。
Enable debug mode to get detailed logs.
Set debug = True in these files:
Restart the reconfigured services
Try to create instance again and check logs.
Take a look at the nova-scheduler.log file and try to find line like this:
.. INFO nova.filters [req-..] Filter DiskFilter returned 0 hosts
Above this line should be DEBUG logs with Filters detailed information, for example:
.. DEBUG nova.filters [req-..] Filter RetryFilter returned 1 host(s) get_filtered_objects /usr/lib/python2.7/site-packages/nova/filters.py:104
.. DEBUG nova.filters [req-..] Filter AvailabilityZoneFilter returned 1 host(s) get_filtered_objects /usr/lib/python2.7/site-packages/nova/filters.py:104
.. DEBUG nova.filters [req-..] Filter RamFilter returned 1 host(s) get_filtered_objects /usr/lib/python2.7/site-packages/nova/filters.py:104
.. DEBUG nova.filters [req-..] (...) ram: 37107MB disk: 11264MB io_ops: 0 instances: 4 does not have 17408 MB usable disk, it only has 11264.0 MB usable disk. host_passes /usr/lib/python2.7/site-packages/nova/scheduler/filters/disk_filter.py:70
OpenStack allows you to overcommit CPU and RAM on compute nodes. This allows you to increase the number of instances running on your cloud at the cost of reducing the performance of the instances. The Compute service uses the following ratios by default:
- CPU allocation ratio: 16:1
- RAM allocation ratio: 1.5:1
Please read documentation to get more information.
请阅读文档以获取更多信息。
You can change allocation ratio using nova.conf:
您可以使用nova.conf更改分配比例：
cpu_allocation_ratioram_allocation_ratiodisk_allocation_ratioFirst you need to check the output of "nova service-list" or "openstack compute service list". It should show at least one 'nova-compute' service with state as "Up" and status as 'enabled'.
首先，您需要检查nova服务列表或OpenStack计算服务列表的输出。它应该至少显示一个状态为“UP”、状态为“Enable”‘nova-Compute’服务。
If the above is fine, then the compute nodes are communicating properly with the scheduler. If not, then you need to check the nova-scheduler logs.
如果上述情况都很好，则说明计算节点与调度程序通信正常。如果没有，那么您需要检查nova-Scheduler日志。
The nova-scheduler has a series of filters like Memory filter, CPU filter, Aggregate filter which it is apply to filter hosts based on the flavor you selected. i.e If you select a flavor with 16GB RAM, then the scheduler will filter (Memory filter) compute hosts which has the available memory. After all the filtering is done the scheduler will try to launch instance on a filtered host, if it fails it will try on another host. Default number of tries is 3. All these can be seen in scheduler logs. That will give you a clear idea on what went wrong.
Nova-Scheduler有一系列过滤器，如内存过滤器、CPU过滤器、聚合过滤器，它根据您选择的风格应用于过滤主机。也就是说，如果您选择16 GB内存的版本，那么调度程序将过滤(内存过滤)具有可用内存的计算主机。在所有过滤完成后，调度程序将尝试在过滤后的主机上启动实例，如果失败，它将在另一台主机上尝试。默认尝试次数为3次。所有这些都可以在调度程序日志中看到。这会让你清楚地知道哪里出了问题。
Also you need to check 'nova show ' output. If you can see the compute host present in "OS-EXT-SRV-ATTR:hypervisor_hostname" , then we can understand that the scheduler was successfully able to allocate a compute host and something went wrong with the compute host. In that case, you need to check the nova-compute logs of that hypervisor.
此外，您还需要检查‘nova show’的输出。如果您可以在“OS-EXT-SRV-ATTR：HYMANDOR_HOSTNAME”中看到计算主机，那么我们就可以理解调度程序能够成功地分配计算主机，并且计算主机出了问题。在这种情况下，您需要检查该管理程序的新计算日志。
Finally I found I mount the /var/lib/nova/ to nfs directory /mnt/sdb/var/lib/nova/, but the /mnt/sdb/var/lib/nova/ permission is root:root, so I changed to the nova:nova(same to the /var/lib/nova/).
最后，我发现我把/var/lib/nova/挂载到nfs目录/mnt/sdb/var/lib/nova/，但是/mnt/sdb/var/lib/nova/权限是root：root，所以我改为nova：nova（和/var/lib/nova/一样）。
command :
命令：
chown -R nova:nova nova
edit /etc/nova/nova.conf in all the compute node and modify as per your application requirement .
在所有计算节点中编辑/etc/nova/nova.conf，并根据您的应用程序需求进行修改。
cpu_allocation_ratio = 2.0
( double of physical core can be used for total instance )ram_allocation_ratio = 2.0
( double of Total memory can be used for total instance
CPU_ALLOCATION_Ratio=2.0(总实例可使用双倍物理核)ram_Allocation_Ratio=2.0(总内存可双倍用于总实例
restart nova and nova-scheduler in all the compute node
在所有计算节点中重新启动nova和nova-Scheduler
systemctl restart openstack-nova-*
System ctl重启OpenStack-nova-*
systemctl restart openstack-nova-scheduler.service
System ctl重启OpenStack-nova-Scheduler.service
29
4
0
我正在使用下面的代码但收到警告， bool versionSupports = (@available(iOS 10, *)); @available does not guard availabil
我需要检查 Xamarin.iOS 中的 API 可用性 - 在 Objective-C 或 Swift 中我可以使用这些调用: if (@available(iOS 13, *)) 或 if #av
我遇到了一个我似乎不明白的奇怪问题。我正在制作一个从文件中读取数据的程序。但是当我读取数据时，我立即收到 EOFException。 所以我用 .available() 检查文件是否为空。我得到了一个
Swift 2.0 允许使用 @available 或 #available 进行可用性检查，但是使用 @available 和 有什么区别#可用? 最佳答案 您可以使用 if #available
我刚刚开始学习 angularjs 我尝试了这段代码:在文件 angularmy.js var myname = angular.module("myModule",[]); myname.contr
我有一个 USB 麦克风和扬声器适配器连接到 raspberry pi 3。我已经在 alsamixer 上设置了所有内容。我也设置了pcm.!default sysdefault:0在文件中 .as
import requests import time import csv import ast import sys import mysql.connector config = { 'user
我想让页脚的宽度与浏览器无关。 对于 Mozilla，我想使用 -moz-available 的值，当用户使用 Opera 时，那么 CSS 应该从 -webkit-fill-available 中获
如果您的代码需要仅在 macOS 10.12 或更高版本中可用的功能，但您希望您的代码也部署到更早的系统版本，您可以使用 @available在 Objective-C 中: if (@availab
我正在使用 Element Query允许在任何元素上使用 @media queries 的元素。这是它的处理方式: #foo:media(min-available-width:350px and
我正在尝试安装 oracle 19c，但在安装过程中遇到了与内存相关的问题“[INS-35179] 当前可用内存小于创建数据库所需的可用内存 (6,537MB)”。我仔细检查了所有先决条件，例如超过
我正在编写代码以使用此页面中的文档跟踪现场请求:http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-spot-instances-bid-
我仔细阅读了 Kubernetes 文档 here关于扩展 imagefs.available 的默认 15%和其他参数，但没有说明如何设置，我已经安装了具有以下配置的 RKE(Rancher Kub
我想进入PAPI。我在Debian GNU/Linux上有5.3.2.0版。 papi_avail告诉我没有可用的硬件事件: $ papi_avail Available events and har
我目前正在构建一个混合云解决方案，需要将消息写入队列以供稍后处理。队列具有高可用性(99.999+% 的正常运行时间)是绝对必要的。 我的选择是将消息读/写到本地 ZeroMQ 高可用性对或 Azur
在 Mac OS X Leopard 中使用 Eclipse Helios 并调试调用 fsf gdb 7.1 的 C++ 代码，调试停止在 main 的第一行。然后在第一步之后我得到 No sour
无论如何，是否可以将 UIWebView 与针对 tvos 的应用程序一起使用？这个苹果文档，UIWebView Class Reference ，会建议否则不是吗？或者我只是解释错了？ UIWebV
我想删除以下数据框中的“不可用”，但是当我使用以下代码将 Number 更改为数字时，“不可用”变为 4: c1 data 是一个 factor 列。 当您将一个因子直接转换为numeric 时，生成
PushKit 在 iOS 11 中提供了一种新方法，旨在取代 iOS 10 中的方法。 使用 iOS 11 作为基础 SDK 构建时无法使用 iOS 10 方法(我当前使用的是 Xcode 9.2B
不确定使用@rename 指令的所有方法。 我正在尝试重命名一个方法 @available(*, deprecated, renamed: "setValueInTable") public func
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