containers | 易学教程

How to SSH into Docker?

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问题 I'd like to create the following infrastructure flow: How can that be achieved using Docker? 回答1: Firstly you need to install a SSH server in the images you wish to ssh-into. You can use a base image for all your container with the ssh server installed. Then you only have to run each container mapping the ssh port (default 22) to one to the host's ports (Remote Server in your image), using -p <hostPort>:<containerPort> . i.e: docker run -p 52022:22 container1 docker run -p 53022:22 container2

Do STL iterators guarantee validity after collection was changed?

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Let's say I have some kind of collection and I obtained an iterator for the beginning of it. Now let's say I modified the collection. Can I still use the iterator safely, regardless of the type of the collection or the iterator? To avoid confusion, here is the order of operations I talk about: Get an iterator of the collection. Modify the collection (obviously not an element in it, but the collection itself). Use the iterator obtained at step 1. Is it stil valid according to STL standard?! Depends on the container. e.g. if it's a vector , after modifying the container all iterators can be

in operator, float(“NaN”) and np.nan

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问题 I used to believe that in operator in Python checks the presence of element in some collection using equality checking == , so element in some_list is roughly equivalent to any(x == element for x in some_list) . For example: True in [1, 2, 3] # True because True == 1 or 1 in [1., 2., 3.] # also True because 1 == 1. However, it is well-known that NaN is not equal to itself. So I expected that float("NaN") in [float("NaN")] is False . And it is False indeed. However, if we use numpy.nan instead

How to get a last element of ES6 Map without iterations?

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问题 How to get a last element of ES6 Map/Set without iterations(forEach or for of) pass through a full length of the container? 回答1: Maps are iterable and ordered, but they are not arrays so they don't have any indexed access. Iterating to the final element is the best you can do. The simplest case being Array.from(map.values()).pop(); 来源： https://stackoverflow.com/questions/30921283/how-to-get-a-last-element-of-es6-map-without-iterations

Is there a sorted collection type in .NET?

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I'm looking for a container that keeps all its items in order. I looked at SortedList, but that requires a separate key, and does not allow duplicate keys. I could also just use an unsorted container and explicitly sort it after each insert. Usage: Occasional insert Frequent traversal in order Ideally not working with keys separate from the actual object, using a compare function to sort. Stable sorting for equivalent objects is desired, but not required. Random access is not required. I realize I can just build myself a balanced tree structure, I was just wondering if the framework already

Why Doesn't string::data() Provide a Mutable char*?

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问题 In c++11 array , string , and vector all got the data method which: Returns pointer to the underlying array serving as element storage. The pointer is such that range [ data() ; data() + size() ) is always a valid range, even if the container is empty. [Source] This method is provided in a mutable and const version for all applicable containers, for example: T* vector<T>::data(); const T* vector<T>::data() const; All applicable containers, that is, except string which only provides the const

docker-compose persistent data on host and container

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问题 I have a problem with volumes in docker-compose yml 3.0+ So I know that a volume behaves like a mount.. But I have set up a wiki and when i set a volume in the docker-compose, the data on the container will be removed (hidden) So how can I save data from my container to my host first and the next time I start the container, it will just overrides the data I saved. So the current situation is: I start with "docker-compose up --build" and a volume is created (empty) and will be copied to the

What's the most standard/generic way to zip a traversable with a list?

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问题 Traversable is in a sense the class of containers whose structure has a “path” (that can correspond to a list), the elements on which can be modified without dissolving the structure. Hence zipTrav :: Traversable t => t a -> [b] -> Maybe (t (a,b)) zipTrav = evalStateT . traverse zp where zp a = do bs <- get case bs of [] -> lift Nothing (b:bs') -> put bs' >> return (a,b) However, that list-state traversal seems a bit hackish and likely not the most efficient way to do it. I'd suppose there

What is the best practice of docker + ufw under Ubuntu

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I just tried out Docker. It is awesome but seems not work nicely with ufw. By default, docker will manipulate the iptables a little bit. The outcome is not a bug but not what I expected. For more details you can read The dangers of UFW + Docker My goal is to set up a system like Host (running ufw) -> docker container 1 - nginx (as a reverse proxy) -> docker container 2 - node web 1 -> docker container 3 - node web 2 -> ....... I want to manage the incoming traffic (e.g. restrict access) through ufw therefore I don't want docker to touch my iptables. Here is my test Environment: a newly

How can I keep a container running on Kubernetes?

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I'm now trying to run a simple container with shell (/bin/bash) on a Kubernetes cluster. I thought that there was a way to keep a container running on a Docker container by using pseudo-tty and detach option ( -td option on docker run command). For example, $ sudo docker run -td ubuntu:latest Is there an option like this in Kubernetes? I've tried running a container by using a kubectl run-container command like: kubectl run-container test_container ubuntu:latest --replicas=1 But the container exits for a few seconds (just like launching with the docker run command without options I mentioned